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Yu, Wen-Kai, Xu-Ri Yao, Xue-Feng Liu, Long-Zhen Li, and Guang-Jie Zhai. "Ghost imaging based on Pearson correlation coefficients." Chinese Physics B 24, no. 5 (April 30, 2015): 054203. http://dx.doi.org/10.1088/1674-1056/24/5/054203.
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Shan, Guogen, Hua Zhang, and Tao Jiang. "Correlation Coefficients for a Study with Repeated Measures." Computational and Mathematical Methods in Medicine 2020 (March 26, 2020): 1–11. http://dx.doi.org/10.1155/2020/7398324.
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Repeated measures are increasingly collected in a study to investigate the trajectory of measures over time. One of the first research questions is to determine the correlation between two measures. The following five methods for correlation calculation are compared: (1) Pearson correlation; (2) correlation of subject means; (3) partial correlation for subject effect; (4) partial correlation for visit effect; and (5) a mixed model approach. Pearson correlation coefficient is traditionally used in a cross-sectional study. Pearson correlation is close to the correlations computed from mixed-effects models that consider the correlation structure, but Pearson correlation may not be theoretically appropriate in a repeated-measure study as it ignores the correlation of the outcomes from multiple visits within the same subject. We compare these methods with regard to the average of correlation and the mean squared error. In general, correlation under the mixed-effects model with the compound symmetric structure is recommended as its correlation is close to the nominal level with small mean square error.
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Edelmann, Dominic, Tamás F. Móri, and Gábor J. Székely. "On relationships between the Pearson and the distance correlation coefficients." Statistics & Probability Letters 169 (February 2021): 108960. http://dx.doi.org/10.1016/j.spl.2020.108960.
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Furman, Edward, and Ričardas Zitikis. "BEYOND THE PEARSON CORRELATION: HEAVY-TAILED RISKS, WEIGHTED GINI CORRELATIONS, AND A GINI-TYPE WEIGHTED INSURANCE PRICING MODEL." ASTIN Bulletin 47, no. 3 (August 7, 2017): 919–42. http://dx.doi.org/10.1017/asb.2017.20.
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AbstractGini-type correlation coefficients have become increasingly important in a variety of research areas, including economics, insurance and finance, where modelling with heavy-tailed distributions is of pivotal importance. In such situations, naturally, the classical Pearson correlation coefficient is of little use. On the other hand, it has been observed that when light-tailed situations are of interest, and hence when both the Gini-type and Pearson correlation coefficients are well defined and finite, these coefficients are related and sometimes even coincide. In general, understanding how these correlation coefficients are related has been an illusive task. In this paper, we put forward arguments that establish such a connection via certain regression-type equations. This, in turn, allows us to introduce a Gini-type weighted insurance pricing model that works in heavy-tailed situations and thus provides a natural alternative to the classical capital asset pricing model. We illustrate our theoretical considerations using several bivariate distributions, such as elliptical and those with heavy-tailed Pareto margins.
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Shieh, Gwowen. "Improved procedures and computer programs for equivalence assessment of correlation coefficients." PLOS ONE 16, no. 5 (May 28, 2021): e0252323. http://dx.doi.org/10.1371/journal.pone.0252323.
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The correlation coefficient is the most commonly used measure for summarizing the magnitude and direction of linear relationship between two response variables. Considerable literature has been devoted to the inference procedures for significance tests and confidence intervals of correlations. However, the essential problem of evaluating correlation equivalence has not been adequately examined. For the purpose of expanding the usefulness of correlational techniques, this article focuses on the Pearson product-moment correlation coefficient and the Fisher’s z transformation for developing equivalence procedures of correlation coefficients. Equivalence tests are proposed to assess whether a correlation coefficient is within a designated reference range for declaring equivalence decisions. The important aspects of Type I error rate, power calculation, and sample size determination are also considered. Special emphasis is given to clarify the nature and deficiency of the two one-sided tests for detecting a lack of association. The findings demonstrate the inappropriateness of existing methods for equivalence appraisal and validate the suggested techniques as reliable and primary tools in correlation analysis.
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Artusi, R., P. Verderio, and E. Marubini. "Bravais-Pearson and Spearman Correlation Coefficients: Meaning, Test of Hypothesis and Confidence Interval." International Journal of Biological Markers 17, no. 2 (April 2002): 148–51. http://dx.doi.org/10.1177/172460080201700213.
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Artusi, R., P. Verderio, and E. Marubini. "Bravais-Pearson and Spearman correlation coefficients: meaning, test of hypothesis and confidence interval." International Journal of Biological Markers 17, no. 2 (2002): 148–51. http://dx.doi.org/10.5301/jbm.2008.2127.
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Masha, Luke, James Stone, Danielle Stone, Jun Zhang, and Luo Sheng. "Pulmonary Catherization Data Correlate Poorly with Renal Function in Heart Failure." Cardiorenal Medicine 8, no. 3 (2018): 183–91. http://dx.doi.org/10.1159/000487203.
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Background: The mechanisms of renal dysfunction in heart failure are poorly understood. We chose to explore the relationship of cardiac filling pressures and cardiac index (CI) in relation to renal dysfunction in advanced heart failure. Objectives: To determine the relationship between renal function and cardiac filling pressures using the United Network of Organ Sharing (UNOS) pulmonary artery catherization registry. Methods: Patients over the age of 18 years who were listed for single-organ heart transplantation were included. Exclusion criteria included a history of mechanical circulatory support, previous transplantation, any use of renal replacement therapy, prior history of malignancy, and cardiac surgery, amongst others. Correlations between serum creatinine (SCr) and CI, pulmonary capillary wedge pressure (PCWP), pulmonary artery systolic pressure (PASP), and pulmonary artery diastolic pressure (PADP) were assessed by Pearson correlation coefficients and simple linear regression coefficients. Results: Pearson correlation coefficients between SCr and PCWP, PASP, and PADP were near zero with values of 0.1, 0.07, and 0.08, respectively (p < 0.0001). A weak negative correlation coefficient between SCr and CI was found (correlation coefficient, –0.045, p = 0.027). In a subgroup of young patients unlikely to have noncardiac etiologies, no significant correlations between these values were identified. Conclusion: These findings suggest that, as assessed by pulmonary artery catherization, none of the factors – PCWP, PASP, PADP, or CI – play a prominent role in cardiorenal syndromes.
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Boucher, Beatrice, Michelle Cotterchio, Nancy Kreiger, Victoria Nadalin, Torin Block, and Gladys Block. "Validity and reliability of the Block98 food-frequency questionnaire in a sample of Canadian women." Public Health Nutrition 9, no. 1 (February 2006): 84–93. http://dx.doi.org/10.1079/phn2005763.
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AbstractObjectiveTo assess the validity and reliability of the most recent adaptation of Block's full-diet food-frequency questionnaire (FFQ) among a sample of Canadian women.DesignParticipants completed a self-administered FFQ (FFQ1), two unannounced 24-hour recalls (weekday and weekend) and a second FFQ (FFQ2) between October 2003 and February 2004. FFQs and recalls were analysed for 32 nutrients using Block Dietary Data Systems and the University of Minnesota's Nutrient Data System. Mean and median intakes were computed, along with crude and deattenuated Pearson correlation coefficients between FFQ1 and the average of two recalls (validity) and between FFQ1 and FFQ2 (reliability).SettingOntario, Canada.SubjectsA random population-based sample (n = 166) of women aged 25 to 74 years.ResultsOne hundred and fifteen (69%) women completed FFQ1, 96 completed FFQ1 and both recalls, and 93 completed both FFQs, about 56 days apart. Mean intakes were similar for most nutrients. FFQ reliability was high, with Pearson correlation coefficients having a median of 0.75, ranging from 0.57 to 0.90 (macronutrients) and from 0.65 to 0.88 (micronutrients from supplements and food). FFQ validity was moderate to high, with deattenuated Pearson correlation coefficients having a median of 0.59, ranging from 0.11 to 0.73 (macronutrients) and from 0.50 to 0.76 (micronutrients from supplements and food). Our micronutrient correlations were similar to or higher than those of other studies that included supplements. Two correlations <0.40 were associated with fats.ConclusionsThe validity and reliability of this full-diet version of the Block FFQ were moderate to high, supporting its use in future studies among Canadian women.
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Kamath, Suneel Deepak. "Disparities in government and nonprofit organization funding may hinder clinical trial development for underfunded cancers." Journal of Clinical Oncology 39, no. 15_suppl (May 20, 2021): 1573. http://dx.doi.org/10.1200/jco.2021.39.15_suppl.1573.
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1573 Background: National Cancer Institute (NCI) and nonprofit organization (NPO) funding is critical for research and advocacy, but may not be equitable across cancers. This could negatively impact clinical trial development for underfunded cancers. Methods: This study evaluated funding from the NCI and NPOs with > $5 million in annual revenue supporting leukemia, lymphoma, melanoma, lung, breast, colorectal, pancreatic, hepatobiliary, prostate, ovarian, cervical and endometrial cancers from 2015-2018 based on publically available reports and tax records. The primary objectives were to assess for disparities in NCI and NPO funding across different cancers compared to their median incidence and mortality from 2015-2018, and to determine if underfunding correlates with fewer clinical trials found in clinicaltrials.gov. Correlations between combined NCI and NPO funding for each cancer and its incidence, mortality and number of clinical trials were evaluated using descriptive statistics and Pearson correlation coefficients. Results: Diseases with the largest combined NCI+NPO funding were breast ($3.75 billion), leukemia ($1.99 billion) and lung cancer ($1.56 billion). Those with the least funding were endometrial ($94 million), cervical ($292 million), and hepatobiliary cancers ($348 million). These data are summarized in the Table. Disease-specific NCI+NPO funding correlated well with incidence, but less so with mortality (Pearson correlation coefficients: 0.74 and 0.63, respectively). Disease-specific NPO funding correlated moderately well with incidence, but was poorly correlated with mortality (Pearson correlation coefficients: 0.54 and 0.39, respectively). Breast cancer, leukemia and lymphoma were consistently well-funded compared to their incidence and mortality, while colorectal, lung, hepatobiliary and uterine cancers were consistently underfunded. The amount of NCI funding, NPO funding and combined NCI+NPO funding for a particular cancer each correlated strongly with the number of clinical trials for that disease (Pearson correlation coefficients: 0.88, 0.87 and 0.91, respectively). Conclusions: Many cancers with high incidence and mortality are underfunded. Cancers with higher mortality rates receive less funding, particularly from NPOs. Underfunding strongly correlates with fewer clinical trials, which could impede future advances in underfunded cancers.[Table: see text]
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Masson, LF, G. MCNeill, JO Tomany, JA Simpson, HS Peace, L. Wei, DA Grubb, and C. Bolton-Smith. "Statistical approaches for assessing the relative validity of a food-frequency questionnaire: use of correlation coefficients and the kappa statistic." Public Health Nutrition 6, no. 3 (June 2003): 313–21. http://dx.doi.org/10.1079/phn2002429.
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AbstractObjective:To compare different statistical methods for assessing the relative validity of a self-administered, 150-item, semi-quantitative food-frequency questionnaire (FFQ) with 4-day weighed diet records (WR).Design:Subjects completed the Scottish Collaborative Group FFQ and carried out a 4-day WR. Relative agreement between the FFQ and WR for energy-adjusted nutrient intakes was assessed by Pearson and Spearman rank correlation coefficients, the percentages of subjects classified into the same and opposite thirds of intake, and Cohen's weighted kappa.Subjects:Forty-one men, mean age 36 (range 21-56) years, and 40 women, mean age 33 (range 19-58) years, recruited from different locations in Aberdeen, Scotland.Results:Spearman correlation coefficients tended to be lower than Pearson correlation coefficients, and were above 0.5 for 10 of the 27 nutrients in men and 17 of the 27 nutrients in women. For nutrients with Spearman correlation coefficients above 0.5, the percentage of subjects correctly classified into thirds ranged from 39 to 78%, and weighted kappa values ranged from 0.23 to 0.66.Conclusions:Both Spearman correlation coefficients and weighted kappa values are useful in assessing the relative validity of estimates of nutrient intake by FFQs. Spearman correlation coefficients above 0.5, more than 50% of subjects correctly classified and less than 10% of subjects grossly misclassified into thirds, and weighted kappa values above 0.4 are recommended for nutrients of interest in epidemiological studies.
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Mokhlessi, Omid, Seyedjavad Seyed Mahdavi Chabok, and Aida Alirezaee. "Selecting effective features from Phonocardiography by Genetic Algorithm based on Pearson`s Coefficients Correlation." Signal and Data Processing 17, no. 3 (November 1, 2020): 157–76. http://dx.doi.org/10.29252/jsdp.17.3.157.
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Mokhlessi, Omid, Seyedjavad Seyed Mahdavi Chabok, and Aida Alirezaee. "Selecting effective features from Phonocardiography by Genetic Algorithm based on Pearson`s Coefficients Correlation." Signal and Data Processing 17, no. 3 (November 1, 2020): 157–76. http://dx.doi.org/10.29252/jsdp.17.3.157.
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Dmytrów, Krzysztof, Anna Gdakowicz, and Ewa Putek-Szeląg. "Methods of Analyzing Qualitative Variable Correlation on the Real Estate Market." Real Estate Management and Valuation 28, no. 1 (March 1, 2020): 80–90. http://dx.doi.org/10.2478/remav-2020-0007.
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AbstractVariables occurring in a real estate market are frequently presented on scales other than interval or ratio scales. Most frequently, the scale is an ordinal (for instance – onerous, unfavourable, neutral, favourable), or possibly a nominal one. That is why the use of scales intended for quantitative attributes (such as Pearson linear correlation coefficient) is not possible. The paper presents the results of employing other coefficients (Kendall’s τB and Spearman’s ρ coefficients) in analyzing correlations on the real estate market.The objective of the article is to present a method of analyzing the correlation of qualitative variables (attributes) and to present the possibility of using the obtained results in the process of real estate appraisal.
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Marques, Rosana de Moraes Borges, Amanda Cristine de Oliveira, Sheylle Almeida da Silva Teles, Maria Luiza Ferreira Stringuini, Nélida Shimid Fornés, and Giulliano Gardenghi. "Relative Validity and Reproducibility of a Quantitative Food Frequency Questionnaire for Adolescents with Type 1 Diabetes: Validity of a Food Frequency Questionnaire." International Journal of Endocrinology 2014 (2014): 1–11. http://dx.doi.org/10.1155/2014/976508.
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Background.Food frequency questionnaires are used to assess dietary intake in epidemiological studies.Objective.The aim of the study was to assess the relative validity and reproducibility of a quantitative food frequency questionnaire (QFFQ) for adolescents with type 1 diabetes. Methods: Validity was evaluated by comparing the data generated by QFFQs to those of 24-hour recalls (24 hrs). QFFQs were applied twice per patient to assess reproducibility. Statistical analysis included performingt-tests, obtaining Pearson correlation coefficients when necessary, correcting measurements for randomness by the weightedkappamethod, calculating intraclass correlation coefficients, and generating Bland-Altman plots (P<0,05).Results.The total energy and nutrient intake as estimated by the QFFQs were significantly higher than those from 24 hrs. Pearson correlation coefficients for energy-adjusted, deattenuated data ranged from 0.32 (protein) to 0.75 (lipid, unsaturated fat and calcium). Weightedkappavalues ranged from 0.15 (vitamin C) to 0.45 (calcium). Bland-Altman plots indicated acceptable validity. As for reproducibility, intraclass correlation coefficients ranged from 0.24 (calcium) to 0.65 (lipid), and the Bland-Altman plots showed good agreement between the two questionnaires. Conclusion: The QFFQ presented an acceptable ability to classify correctly and with good reproducibility, adolescents with type 1 diabetes according to their levels of dietary intake.
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Cardoso, Marly Augusto, Luciana Yuki Tomita, and Elaine Cristina Laguna. "Assessing the validity of a food frequency questionnaire among low-income women in São Paulo, southeastern Brazil." Cadernos de Saúde Pública 26, no. 11 (November 2010): 2059–67. http://dx.doi.org/10.1590/s0102-311x2010001100007.
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This study describes the validity of a food frequency questionnaire (FFQ) in 93 low-income women (20-65 years), participating in a case-control study in São Paulo, Brazil. Two FFQ (FFQ1 and FFQ2, 12 months apart) and three 24-hour dietary recalls (24hR) were conducted between 2003 and 2004 to estimate dietary intake during the past year. The Pearson correlation coefficients (crude, energy-adjusted and de-attenuated) were used for comparisons between FFQ and 24hR. The agreement between the methods was further examined by the Bland-Altman analysis. For the assessment of long-term reliability, the energy-adjusted intra-class correlation coefficients were mostly around 0.40, but higher for vitamin A and folate (0.50-0.56). Energy-adjusted, attenuation-corrected Pearson validity correlations between FFQ and DR ranged from 0.30-0.54 for macronutrients to 0.20-0.48 for micronutrients, with higher value for calcium (0.75). There were small proportions of grossly misclassified nutrient intakes, while Bland-Altman plots indicated that the FFQ is accurate in assessing nutrient intake at a group level.
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Śleszyński, Zbigniew. "The basics of determining the coefficients of a linear correlation." Wiadomości Statystyczne. The Polish Statistician 65, no. 6 (June 30, 2020): 69–87. http://dx.doi.org/10.5604/01.3001.0014.2347.
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The aim of the paper is to present the basic measures related to the analysis of relationships between quantitative variables used in econometric modelling and their selected applications. The following measures are discussed: the Pearson correlation coefficient, the multivariate correlation coefficient, coefficient of determination, partial correlation coefficient and semi-partial correlation coefficient. A homogeneous approach is applied to the measures presented. Each is defined as a linear correlation coefficient of relevant vectors derived from regression equations. Additionally, mutual relations between the coefficients are described. Bordered matrices have been applied to the calculations, which significantly simplified the process, while the Statistica 13.3 PL program was used to verify the correctness of the calculations. The issue is illustrated in the model of regression of salary growth in Poland in the years 2001–2019 with four covariates, estimated using the least squares method.
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Gao, Jia, Wei Wang, and Ji Zhang. "Explore Interregional EEG Correlations Changed by Sport Training Using Feature Selection." Computational Intelligence and Neuroscience 2016 (2016): 1–10. http://dx.doi.org/10.1155/2016/6184823.
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This paper investigated the interregional correlation changed by sport training through electroencephalography (EEG) signals using the techniques of classification and feature selection. The EEG data are obtained from students with long-time professional sport training and normal students without sport training as baseline. Every channel of the 19-channel EEG signals is considered as a node in the brain network and Pearson Correlation Coefficients are calculated between every two nodes as the new features of EEG signals. Then, the Partial Least Square (PLS) is used to select the top 10 most varied features and Pearson Correlation Coefficients of selected features are compared to show the difference of two groups. Result shows that the classification accuracy of two groups is improved from 88.13% by the method using measurement of EEG overall energy to 97.19% by the method using EEG correlation measurement. Furthermore, the features selected reveal that the most important interregional EEG correlation changed by training is the correlation between left inferior frontal and left middle temporal with a decreased value.
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Zhuang, H., and E. M. Savage. "Variation and Pearson correlation coefficients of Warner-Bratzler shear force measurements within broiler breast fillets." Poultry Science 88, no. 1 (January 2009): 214–20. http://dx.doi.org/10.3382/ps.2007-00442.
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Um, Seoho, and John L. Crompton. "The Importance of Testing for a Significant Difference Between Two Pearson Product-Moment Correlation Coefficients." Journal of Leisure Research 18, no. 3 (July 1986): 206–9. http://dx.doi.org/10.1080/00222216.1986.11969658.
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Young, Thomas J., and Laurence A. French. "Taxable Wealth and Alcoholic Beverage Consumption in the United States." Psychological Reports 74, no. 3 (June 1994): 813–14. http://dx.doi.org/10.2466/pr0.1994.74.3.813.
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Analysis of secondary data of the United States yielded significant but small Pearson correlation coefficients between taxable wealth and per capita consumption of wine ( r = .26), beer ( r = .40), and distilled spirits ( r = .30).
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Rodríguez, Monica M., Humberto Méndez, Benjamín Torún, Dirk Schroeder, and Aryeh D. Stein. "Validation of a semi-quantitative food-frequency questionnaire for use among adults in Guatemala." Public Health Nutrition 5, no. 5 (October 2002): 691–98. http://dx.doi.org/10.1079/phn2002333.
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AbstractObjective:The purpose of the study was to assess the validity of a 52-item semiquantitative food-frequency questionnaire (FFQ) by comparing it with multiple 24-hour dietary recalls.Design:Three non-consecutive 24-hour dietary recalls and one FFQ were administered over a one-month period.Setting:Four communities of El Progreso, Guatemala.Subjects:Seventy-three individuals aged 22–55 years.Results:Intakes of energy and other nutrients as measured by the FFQ were higher than intakes measured by 24-hour recalls. Energy was overestimated by 361 kcal, and nutrient overestimates were particularly great for vitamin C and iron. Pearson correlation coefficients for crude energy and nutrients intakes ranged from 0.64 for energy to 0.12 for vitamin C. Exact agreement for both methods (measured by the concordance correlation coefficient) ranged from 0.59 (fat) to 0.06 (vitamin C). Pearson correlation coefficients for energy-adjusted nutrients ranged from 0.59 (carbohydrates) to 0.11 (thiamin). Pearson correlation coefficients for the proportion of total energy derived from specific foods ranged from 0.59 (tortillas) to 0.01 (sugared beverages). Cross-classification of quartiles of crude nutrient intakes for both methods indicated that <11% were grossly misclassified; after adjusting for energy intake, <13% were grossly misclassified.Conclusions:This FFQ provides good measures of energy and macronutrient intakes and a reasonably reliable measure of micronutrient intake, indicating its suitability for comparing exposures within a study population in reference to heath-related endpoints. Our results highlight the need to adapt any FFQ to specific cultural needs – in this case, the Guatemalan ‘core foods’ (tortilla, bread and beans), for which inter-individual variability in intake is high.
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Dehghan, Mahshid, Solange Martinez, Xiaohe Zhang, Pamela Seron, Fernando Lanas, Shofiqul Islam, and Anwar T. Merchant. "Relative validity of an FFQ to estimate daily food and nutrient intakes for Chilean adults." Public Health Nutrition 16, no. 10 (September 21, 2012): 1782–88. http://dx.doi.org/10.1017/s1368980012004107.
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AbstractObjectiveFFQ are commonly used to rank individuals by their food and nutrient intakes in large epidemiological studies. The purpose of the present study was to develop and validate an FFQ to rank individuals participating in an ongoing Prospective Urban and Rural Epidemiological (PURE) study in Chile.DesignAn FFQ and four 24 h dietary recalls were completed over 1 year. Pearson correlation coefficients, energy-adjusted and de-attenuated correlations and weighted kappa were computed between the dietary recalls and the FFQ. The level of agreement between the two dietary assessment methods was evaluated by Bland–Altman analysis.SettingTemuco, Chile.SubjectsOverall, 166 women and men enrolled in the present study. One hundred men and women participated in FFQ development and sixty-six individuals participated in FFQ validation.ResultsThe FFQ consisted of 109 food items. For nutrients, the crude correlation coefficients between the dietary recalls and FFQ varied from 0·14 (protein) to 0·44 (fat). Energy adjustment and de-attenuation improved correlation coefficients and almost all correlation coefficients exceeded 0·40. Similar correlation coefficients were observed for food groups; the highest de-attenuated energy-adjusted correlation coefficient was found for margarine and butter (0·75) and the lowest for potatoes (0·12).ConclusionsThe FFQ showed moderate to high agreement for most nutrients and food groups, and can be used to rank individuals based on energy, nutrient and food intakes. The validation study was conducted in a unique setting and indicated that the tool is valid for use by adults in Chile.
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Cornwall, Mark W., and Thomas G. McPoil. "Reliability and Validity of Center-of-Pressure Quantification." Journal of the American Podiatric Medical Association 93, no. 2 (March 1, 2003): 142–49. http://dx.doi.org/10.7547/87507315-93-2-142.
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The purpose of this study was to determine the reliability and validity of two center-of-pressure quantification methods. One hundred five individuals (33 men and 72 women) with a mean age of 26.7 years participated in phase 1 of the study. Two measures of the center-of-pressure pattern, the lateral-medial area index and the lateral-medial force index, were calculated from plantar pressure data collected on all subjects. Between-trial reliability of the two measurements was assessed using intraclass correlation coefficients. In phase 2, frontal plane motion of the rearfoot was recorded in 30 individuals. Pearson correlation coefficients were then calculated between the two center-of-pressure indices and the magnitude of rearfoot eversion obtained from each subject during walking. Intraclass correlation coefficient values ranged from 0.374 to 0.889 for the lateral-medial area index and from 0.215 to 0.905 for the lateral-medial force index. Pearson correlation coefficients between the two center-of-pressure indices and the rearfoot kinematic variables ranged from 0.050 to 0.165. The lateral-medial area index and the lateral-medial force index may have adequate between-trial reliability but are not related to the magnitude of frontal plane rearfoot eversion during the stance phase of walking. (J Am Podiatr Med Assoc 93(2): 142-149, 2003)
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Schubert, Emery. "Correlation analysis of continuous emotional response to music: Correcting for the effects of serial correlation." Musicae Scientiae 5, no. 1_suppl (September 2001): 213–36. http://dx.doi.org/10.1177/10298649020050s108.
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Publications of research concerning continuous emotional responses to music are increasing. The developing interest brings with it a need to understand the problems associated with the analysis of time series data. This article investigates growing concern in the use of conventional Pearson correlations for comparing time series data. Using continuous data collected in response to selected pieces of music, with two emotional dimensions for each piece, two falsification studies were conducted. The first study consisted of a factor analysis of the individual responses using the original data set and its first-order differenced transformation. The differenced data aligned according to theoretical constraints better than the untransformed data, supporting the use of first-order difference transformations. Using a similar method, the second study specifically investigated the relationship between Pearson correlations, difference transformations and the critical correlation coefficient above which the conventional correlation analysis remains internally valid. A falsification table was formulated and quantified through a hypothesis index function. The study revealed that correlations of undifferenced data must be greater than 0.75 for a valid interpretation of the relationship between bivariate emotional response time series data. First and second-order transformations were also investigated and found to be valid for correlation coefficients as low as 0.24. Of the three version of the data (untransformed, first-order differenced, and second-order differenced), first-order differenced data produced the fewest problems with serial correlation, whilst remaining a simple and meaningful transformation.
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De Mits, Sophie, Pascal Coorevits, Dirk De Clercq, Dirk Elewaut, James Woodburn, and Philip Roosen. "Reliability and Validity of the INFOOT Three-dimensional Foot Digitizer for Patients with Rheumatoid Arthritis." Journal of the American Podiatric Medical Association 101, no. 3 (May 1, 2011): 198–207. http://dx.doi.org/10.7547/1010198.
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Background: Abnormal foot posture and deformities are identified as important features in rheumatoid arthritis. There is still no consensus regarding the optimum technique(s) for quantifying these features; hence, a foot digitizer might be used as an objective measurement tool. We sought to assess the validity and reliability of the INFOOT digitizer. Methods: To investigate the validity of the INFOOT digitizer compared with clinical measurements, we calculated Pearson correlation coefficients. To investigate the reliability of the INFOOT digitizer, we calculated intraclass correlation coefficients, SEMs, smallest detectable differences, and smallest detectable difference percentages. Results: Most of the 38 parameters showed good intraclass correlation coefficients, with values greater than 0.9 for 30 parameters and greater than 0.8 for seven parameters. The left heel bone angle expressed a moderate correlation, with a value of 0.609. The SEM values varied between 0.31 and 3.51 mm for the length and width measures, between 0.74 and 5.58 mm for the height data, between 0.75 and 5.9 mm for the circumferences, and between 0.78° and 2.98° for the angles. The smallest detectable difference values ranged from 0.86 to 16.36 mm for length, width, height, and circumference measures and from 2.17° to 8.26° for the angle measures. For the validity of the INFOOT three-dimensional foot digitizer, Pearson correlation coefficients varied between 0.750 and 0.997. Conclusions: In this rheumatoid arthritis population, good validity was demonstrated compared with clinical measurements, and most of the obtained parameters proved to be reliable. (J Am Podiatr Med Assoc 101(3): 198–207, 2011)
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Walsh, Jessica A., Huaming Tan, Hernan Valdez, and Kristina Callis Duffin. "Comparative Assessment of PASI and Variations of PGA×BSA as Measures of Psoriasis Severity." Journal of Psoriasis and Psoriatic Arthritis 2, no. 4 (September 2017): 113–18. http://dx.doi.org/10.1177/247553031700200409.
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Background Commonly used instruments for measuring psoriasis, such as Psoriasis Area and Severity Index (PASI), have limitations, including high complexity. Objective Determine if PGA×BSA or PGA×√BSA are practical alternatives to PASI for measuring severity and treatment response. Methods Data from a Phase 3 study in 1,101 patients treated for moderate to severe psoriasis were used. PASI was the reference standard. Correlations (Pearson coefficients), test-retest reliability (intraclass correlation coefficients), responsiveness to treatment (percentage change and effect size), and correspondence (sensitivity and specificity) were assessed. Results Correlation coefficients of change (baseline at Week 12) were 0.90 between PASI and either PGA×BSA and PGA×√BSA. ICCs were 0.90. Both instruments demonstrated similar percentage change from baseline and effect sizes. Sensitivities of PGA×BSA and PGA×√BSA were 99% and 95%, and specificities were 76% and 87%, respectively. Conclusions PGA×BSA and PGA×√BSA had similar measurement properties as PASI. PGA×BSA is a practical alternative to PASI.
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Mji, Andile. "Conceptions of and Approaches to Learning Mathematics." Psychological Reports 87, no. 3 (December 2000): 971–72. http://dx.doi.org/10.2466/pr0.2000.87.3.971.
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Pearson correlation coefficients indicated a different relationship between conceptions of mathematics and approaches to learning mathematics to that reported in literature. It was concluded that the 154 students (82 women and 72 men) followed a strategic approach to learning mathematics.
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Barducci, Robson S., Ziyu Y. Zhou, Lisa Wormsbecher, Colleen Roehrig, Dan Tulpan, and Benjamin M. Bohrer. "The relationship of pork carcass weight and leanness parameters in the Ontario commercial pork industry." Translational Animal Science 4, no. 1 (October 23, 2019): 331–38. http://dx.doi.org/10.1093/tas/txz169.
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Abstract This study aimed to examine the correlation of carcass weight, fat depth, muscle depth, and predicted lean yield in commercial pigs. Data were collected on 850,819 pork carcasses from the same pork processing facility between October 2017 and September 2018. Hot carcass weight was reported following slaughter as a head-on weight; while fat and muscle depth were measured with a Destron PG-100 probe and used for the calculation of predicted lean yield based on the Canadian Lean Yield (CLY) equation [CLY (%) = 68.1863 − (0.7833 × fat depth) + (0.0689 × muscle depth) + (0.0080 × fat depth2) − (0.0002 × muscle depth2) + (0.0006 × fat depth × muscle depth)]. Descriptive statistics, regression equations including coefficients of determination, and Pearson product moment correlation coefficients (when assumptions for linearity were met) and Spearman’s rank-order correlation coefficients (when assumptions for linearity were not met) were calculated for attributes using SigmaPlot, version 11 (Systat Software, Inc., San Jose, CA). Weak positive correlation was observed between hot carcass weight and fat depth (r = 0.289; P < 0.0001), and between hot carcass weight and muscle depth (r = 0.176; P < 0.0001). Weak negative correlations were observed between hot carcass weight and predicted lean yield (r = −0.235; P < 0.0001), and between fat depth and muscle depth (r = −0.148; P < 0.0001). Upon investigation of relationships between fat depth and predicted lean yield, and between muscle depth and predicted lean yield using scatter plots, it was determined that these relationships were not linear and therefore the assumptions of Pearson product moment correlation were not met. Thus, these relationships were expressed as nonlinear functions and Spearman’s rank-order correlation coefficients were used. A strong negative correlation was observed between fat depth and predicted lean yield (r = −0.960; P < 0.0001), and a moderate positive correlation was observed between muscle depth and predicted lean yield (r = 0.406; P < 0.0001). Results from this dataset revealed that hot carcass weight was generally weakly correlated (r < |0.35|) with fat depth, muscle depth, and predicted lean yield. Therefore, it was concluded that there were no consistent weight thresholds where pigs were fatter or heavier muscled.
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Arena, John G., and Stephen H. Hobbs. "Temporal Stability of Psychophysiological Stress Profiles: A Re-Analysis Using Intraclass Correlation Coefficients." Psychological Reports 76, no. 1 (February 1995): 171–75. http://dx.doi.org/10.2466/pr0.1995.76.1.171.
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This is a re-analysis of data from a previous study which examined the temporal stability of three psychophysiological responses [frontal electromyographic activity (EMG), hand surface temperature, and heart rate]. Each response was recorded on 64 subjects over four sessions, each of which consisted of a 20-min. adaptation period, a baseline condition, and two stressors (one cognitive, the other physical). Rather than using Pearson product-moment correlations, as nearly all psychophysiological test-retest reliability studies have, we have now analyzed the data using intraclass correlation coefficients. This type of correlation allows one to incorporate more than two test-retest values on the same subjects. Analysis indicated that, with the exception of EMG during the physical stressor, the absolute values of the responses had quite significant reliability (.70 or greater). Treating the responses as relative measures (percent change from baseline or simple change scores from baseline) produced smaller and frequently less stable coefficients. It is concluded that statistical estimates of psychophysiological response reliability are functions of the design and particular reliability analysis employed.
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Kamath, Suneel D., Sheetal M. Kircher, and Al B. Benson. "Comparison of Cancer Burden and Nonprofit Organization Funding Reveals Disparities in Funding Across Cancer Types." Journal of the National Comprehensive Cancer Network 17, no. 7 (July 2019): 849–54. http://dx.doi.org/10.6004/jnccn.2018.7280.
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AbstractBackground: Nonprofit organizations (NPOs) in oncology are vital for patient advocacy and funding research for rare cancers, young investigators, and innovative projects. However, some cancers may be underfunded relative to their burden. This study examined the alignment of cancer burden by histology with NPO funding for each histology. Patients and Methods: This nationwide, cross-sectional study conducted from October 2017 through February 2018 included all oncology NPOs with >$5 million in annual revenue. Total revenue from NPOs supporting individual cancer types with the incidence, mortality, and person-years of life lost (PYLL) for each cancer type was compared using scatter plots and Pearson correlation coefficients. Correlation of expenditure types (eg, fundraising, patient education) with revenue was assessed using Pearson correlation coefficients. Effect of disease association with a stigmatized behavior (eg, lung cancer and smoking) was evaluated using descriptive statistics. Results: A total of 119 cancer-related NPOs were included, generating approximately $6 billion in annual revenue in 2015. Cancers with the largest revenue were breast cancer ($460 million; 33.2%), leukemia ($201 million; 14.5%), pediatric cancers ($177 million; 12.8%), and lymphoma ($145 million; 10.5%). Breast cancer, leukemia, lymphoma, and pediatric cancers were all well funded compared with their incidence, mortality, and PYLL. Gastrointestinal (colorectal, pancreas, and hepatobiliary), gynecologic (ovarian, cervical, and endometrial), brain, and lung cancers were poorly funded in all 3 metrics. All cancers associated with a stigmatized behavior were poorly funded in at least 2 metrics. Increased spending on fundraising, administrative costs, patient education, and treatment was highly correlated with increased revenue (Pearson correlation coefficients all >0.92). Conclusions: NPO funding by cancer type is not proportionate with individual cancer burden on society. Disease stigma negatively impacts funding. A significant need exists to increase awareness and funding for many undersupported but common and highly lethal cancers.
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Abdel-Khalek, Ahmed M. "Two Scales of Death Anxiety: Their Reliability and Correlation among Kuwaiti Samples." Perceptual and Motor Skills 84, no. 3 (June 1997): 921–22. http://dx.doi.org/10.2466/pms.1997.84.3.921.
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Arabic versions of the Templer Death Anxiety Scale and the Thorson and Powell Revised Death Anxiety Scale were administered to 117 male and 157 female Kuwaiti undergraduates. Cronbach coefficients alpha for the two scales were, respectively, .79 and .77. Pearson correlations for scores on the two scales were .54, .67, and .64 for men, women and the combined group, respectively, so reliability and concurrent validity of the scales were adequate for the Kuwaiti sample.
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de Carvalho Rosas Gomes, Liliane, Karla Orfelina Carpio Horta, Luiz Gonzaga Gandini, Marcelo Gonçalves, and João Roberto Gonçalves. "Photographic assessment of cephalometric measurements." Angle Orthodontist 83, no. 6 (April 18, 2013): 1049–58. http://dx.doi.org/10.2319/120712-925.1.
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ABSTRACT Objective: To investigate the relationship between craniofacial measurements obtained from cephalometric radiographs and analogous measurements from profile photographs. Materials and Methods: Lateral cephalograms and standardized facial profile photographs were obtained from a sample of 123 subjects (65 girls, 58 boys; age 7–12 years). Intraclass correlation coefficients (ICCs) were calculated from repeated photographic measurements to evaluate method reliability. Analogous cephalometric and photographic measurements were compared to assess Pearson correlation coefficients. Linear regression analyses were conducted between the measurements that achieved correlation coefficients greater than r = 0.7. Results: The reliability of the photographic technique was satisfactory. Most measurements showed ICCs above 0.80 and highly significant correlations (P ≤ .001) with cephalometric variables. Among all measurements used, the A'N'B' angle was the most effective in explaining the variability of its analogous cephalometric, mainly for female subjects (r2 = 0.80). The FMA' angle showed the best results for vertical assessment (r2 = 0.65). Conclusions: The photographic method has proven to be a repeatable and reproducible tool provided that a standardized protocol is followed. Therefore, it may be considered a feasible and practical diagnostic alternative, particularly if there is a need for a low-cost and noninvasive method.
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Lacher, D. A. "Relationship between delta checks for selected chemistry tests." Clinical Chemistry 36, no. 12 (December 1, 1990): 2134–36. http://dx.doi.org/10.1093/clinchem/36.12.2134.
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Abstract The correlation between delta differences for 20 serum chemistry tests was calculated for 2400 samples from 288 patients. There were 12 pairs of chemistry tests for which correlation coefficients of the delta checks exceeded 0.25; aspartate aminotransferase and alanine aminotransferase had the highest Pearson correlation coefficient, 0.915. The highest negative, indirect, correlation was between the delta checks of bicarbonate and chloride (-0.219). The relationship between delta differences may be used as a quality-control technique to detect analytical errors.
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Vališ, David, and Libor Žák. "Approaches in Correlation Analysis and Application on Oil Field Data." Applied Mechanics and Materials 841 (June 2016): 77–82. http://dx.doi.org/10.4028/www.scientific.net/amm.841.77.
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The paper deals with selected approaches which unite several correlation analysis principles. Field data very often has various forms and contents. The comparison of different approaches will help to determine more precisely which correlation analysis is better for assessing input and output data. In this paper we introduce several correlation principles which can help to select the most suitable correlation approach. We present a traditional correlation analysis and compare it with Pearson and Spearman correlation coefficients. The value of our article lies in comparing several different approaches of the correlation analysis in which the oil field data from diesel combustion engine are used
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Rezaee, Zabihollah, Sara Aliabadi, Alireza Dorestani, and Nick J. Rezaee. "Application of Time Series Models in Business Research: Correlation, Association, Causation." Sustainability 12, no. 12 (June 12, 2020): 4833. http://dx.doi.org/10.3390/su12124833.
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Time series models are used to determine relationships, spot patterns, and detect abnormalities and irregularities among data. We explore the application of time series analyses in business research by discussing the differences among correlation, association, and Granger causality and providing insight into their proper use in the sustainability literature. In statistics, two correlation coefficients are typically calculated. The first one is the Pearson correlation coefficient and the second is the Spearman correlation coefficient. In the commonly used correlation analysis (the Pearson and the Spearman correlation coefficients), the focus is primarily on the changes in two variables regardless of the effects of other variables. On the contrary, in association analyses, the researcher examines the relationship between two variables while holding the effects of other related variables constant (ceteris paribus). In the study of the causation, or the cause–effect relationship between two variables, researchers are concerned about the effect of variable X on variable Y. The difficulty of achieving the third condition of causation is believed to be the main reason that in business literature causations are rarely used. The difficulty of achieving a causal relationship between two variables has moved researchers toward a special form of causation called “Granger causality”. We offer practical examples for correlation, association, causation, and the Granger causality and discuss their main differences and show how the use of a linear regression is inappropriate when the true relationship is non-linear. Finally, we discuss the policy, practical, and educational implications of our study.
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Loturco, Irineu, Lucas Pereira, Ronaldo Kobal, Cesar Cal Abad, Victor Fernandes, Rodrigo Ramirez-Campillo, and Timothy Suchomel. "Portable Force Plates: A Viable and Practical Alternative to Rapidly and Accurately Monitor Elite Sprint Performance." Sports 6, no. 3 (July 12, 2018): 61. http://dx.doi.org/10.3390/sports6030061.
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This study aimed to examine the associations between a series of mechanical variables automatically generated by a portable force plate (PFP) and the actual performance of professional sprinters over a 150 m course. To test these correlations, 12 top-level sprinters performed vertical jumps (squat and countermovement jumps; SJ and CMJ, respectively), a 60 m sprint test, and a 150 m sprint test. Pearson product-moment coefficient of correlation and multiple regression analyses were used to determine the relationships between the sprinting velocities and vertical jump outputs. The SJ parameters were moderately to near perfectly associated with the different sprint distances, and the SJ height presented the highest correlation scores (r = 0.90 with velocities over 10- and 20-m). The correlation coefficients between the CMJ outcomes and sprint results varied between moderate and very large (from 0.38 to 0.88). Finally, the coefficients of determination (R2) ranged from 0.71 to 0.85 for the different multiple regressions involving PFP automatic measures. The PFP can provide practitioners with quick and accurate information regarding competitive athletes. Due to the strong correlations observed, coaches are encouraged to frequently adjust and tailor the training strategies of their sprinters, using practical and timesaving PFP measurements.
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Lawson, Thomas T., and Larry D. Evans. "Stanford-Binet: Fourth Edition Short Forms with Underachieving and Learning Disabled Students." Psychological Reports 79, no. 1 (August 1996): 47–50. http://dx.doi.org/10.2466/pr0.1996.79.1.47.
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55 students referred to a Child Development Center for academic underachievement and suspected learning disabilities were administered the Stanford-Binet Intelligence Scale: Fourth Edition. Pearson product-moment correlation coefficients of .98, .95, and .90 were obtained for the Test Composite with those for 6-, 4-, and 2-test Partial Composites derived from this administration, respectively. These values are compared with coefficients reported for other populations, and the suitability of the Stanford-Binet Partial Composites for screening underachievement and learning disabilities is discussed.
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Gholipour, Zahra, Seyed Ali Siadat, and Mohammad Taghi Mahmoudi. "Investigating the Relationship between Talent Management Strategy and Career Path of Principals of Schools in Shahr-e-Kord." International Research in Education 4, no. 1 (February 12, 2016): 39. http://dx.doi.org/10.5296/ire.v4i1.9007.
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The aim of the present study is to investigate the relationship between talent management strategy and career path in principals of schools in Shahr-e-Kord. The study is a descriptive-correlational one and its population includes all principals of high schools in Areas 1 and 2 of Shahr-e-Kord equal as 103 individuals in the academic year 2014-2015. A number of 81 principals were selected as participants via the simple random sampling and using Chochrane’s formula. To measure talent management, the Sweem standard questionnaire and to measure career path, the Schaufeli standard questionnaire were used. The reliability coefficients for the questionnaires were calculated using Chronbach’s alpha coefficients as 0.85 and 0.84 respectively. Data analysis was conducted using Pearson correlation coefficient and regression coefficient by SPSS. The results indicated that talent management strategy has a positive and significant correlation with principals’ career path of principals of schools in Shahr-e-Kord. In addition, there is a direct and significant correlation between components of communication, performance management, training the staff and in acknowledgment of individuals with career path.
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Petropoulos, G., C. Pandazaras, and I. Stamos. "Study of the main variability aspects of surface texture of steel in face milling." Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology 217, no. 2 (February 1, 2003): 175–80. http://dx.doi.org/10.1243/13506500360603606.
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The investigation of basic variability aspects in face-milled surfaces regarding roughness and waviness (surface texture) for various cutting conditions is attempted in this note. The inhomogeneity of the machined steel specimens surfaces is modelled according to the Fisher-Pearson statistical system. Models are developed by regression analysis for waviness and roughness interdependence exhibiting very high correlation coefficients.
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Notario-Barandiaran, Leyre, Carmen Freire, Manuela García-de-la-Hera, Laura Mª Compañ-Gabucio, Laura Torres-Collado, Sandra González-Palacios, Antonio Mundo, Marina Molina, Mariana F. Fernández, and Jesús Vioque. "Reproducibility and Validity of a Food Frequency Questionnaire for Dietary Assessment in Adolescents in a Self-Reported Way." Nutrients 12, no. 7 (July 14, 2020): 2081. http://dx.doi.org/10.3390/nu12072081.
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Tools to assess diet in a reliable and efficient way are needed, particularly in children and adolescents. In this study, we assess the reproducibility and validity of a semiquantitative food frequency questionnaire (FFQ) among adolescents in Spain. We analyzed data of 51 male adolescents aged 15–17 years from a prospective birth cohort study. Participants answered the FFQ twice in a self-administered way over a 12-month period. Reproducibility was assessed by comparing nutrient and food intakes from the FFQs, and validity by comparing nutrient intakes from the average of two FFQs and the average of two 24-Hour Dietary Recalls obtained in the period. Pearson correlation coefficients were calculated. The average of reproducibility correlation coefficients for food group intakes was 0.33, with the highest correlation for vegetable intake (r = 0.81); and the average for nutrient intake was 0.32, with the highest coefficients for α- and β-carotene (r = 0.65). Validity correlation coefficients ranged from 0.07 for carbohydrates to 0.53 for dietary fiber. The average of the validity correlation coefficients was r = 0.32. This study suggests that our FFQ may be a useful tool for assessing dietary intake of most nutrient and food groups among Spanish male adolescents in a self-administered way, despite reproducibility and, particularly validity, being low for some nutrients and food groups.
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Johansson, Ingegerd, Göran Hallmans, Åsa Wikman, Carine Biessy, Elio Riboli, and Rudolf Kaaks. "Validation and calibration of food-frequency questionnaire measurements in the Northern Sweden Health and Disease cohort." Public Health Nutrition 5, no. 3 (June 2002): 487–96. http://dx.doi.org/10.1079/phn2001315.
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AbstractObjectives:To evaluate the reproducibility of, and to compare and calibrate, diet measures by the Northern Sweden 84-item food-frequency questionnaire (FFQ) with measures from 24-hour diet recalls (24-HDR).Design:Randomly selected respondents (n=246) from the EPIC (diet-cancer) and MONICA (diet-cardiovascular disease) study cohort in Northern Sweden were invited to answer the FFQ twice over a one-year interval (FFQ1 and FFQ2), and to complete ten 24-hour recalls (reference method) in the months between. Plasma β-carotene concentrations were determined from a subset of 47 participants.Setting:Vasterbotten and Norrbotten, Northern Sweden.Participants:Ninety-six men and 99 women, who completed the study.Results:The reproducibility of the FFQ was high in terms of both mean energy and nutrient intakes and relative ranking of participants by intake levels (median Pearson correlation of 0.68). Moderately higher food intake frequencies were recorded by FFQ1 compared with 24-hour recalls for dairy products, bread/cereals, vegetables, fruits and potato/rice/pasta, whereas meat, fish, sweet snacks and alcoholic beverage intakes were lower. The median Spearman coefficient of correlation between FFQ1 and the average of ten 24-HDR measurements was 0.50. Daily energy and nutrient intakes were similar for FFQ1 and 24-HDR measurements, except for fibre, vitamin C, β-carotene and retinol (FFQ1<24-HDR) and sucrose and cholesterol (FFQ1>4-HDR). Pearson coefficients of correlation between FFQ1 and 24-HDR corrected for attenuation due to residual day-to-day variation in the 24-HDR measurements ranged from 0.36 to 0.79 (median 0.54). Adjustment for energy had only very moderate effects on the correlation estimates. Calibration coefficients estimated by linear regression of the 24-HDR on the FFQ1 measurements varied between 0.30 and 0.59 for all nutrients except alcohol, which had calibration coefficients close to 1.0. These low calibration coefficients indicate that relative risk estimates corresponding to an absolute difference in dietary intake levels measured by the FFQ will generally be biased towards 1.0. Plasma β-carotene levels had a Pearson coefficient of correlation of 0.47 with the 24-HDR measurements, and of 0.23 with FFQ1 measurements.Conclusions:The Northern Sweden FFQ measurements have good reproducibility and an estimated level of validity similar to that of FFQ measurements in other prospective cohort studies. The results from this study will form the basis for the correction of attenuation and regression dilution biases in relative risk estimates, in future studies relating FFQ measurements to disease outcomes.
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Spirrison, Charles L., and Suksoon Choi. "Psychometric Properties of a Korean Version of the Revised Neo-Personality Inventory." Psychological Reports 83, no. 1 (August 1998): 263–74. http://dx.doi.org/10.2466/pr0.1998.83.1.263.
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Native Korean speakers attending English-speaking universities in the United States (47 men, 37 women) were administered Form S (self-report) or Form R (observer's ratings) of both the English and Korean language versions of the Revised NEO-Personality Inventory. Analyses of internal consistency reliability, Pearson correlation coefficients, and t tests computed across languages and within forms suggested chat the Korean translations of Form S and Form R were essentially equivalent to the English originals. Using the Korean versions of the Form S and Form R domains, correlations were computed between self-reported personality traits and the traits as rated by each participant's spouse. The resulting correlation matrix supported the convergent and discriminant validity of this Korean translation of the Revised NEO-Personality Inventory.
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Headrick, Todd Christopher. "A Note on the Relationship between the Pearson Product-Moment and the Spearman Rank-Based Coefficients of Correlation." Open Journal of Statistics 06, no. 06 (2016): 1025–27. http://dx.doi.org/10.4236/ojs.2016.66082.
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O'Donnell, M. G., M. Nelson, P. H. Wise, and D. M. Walker. "A computerized diet questionnaire for use in diet health education." British Journal of Nutrition 66, no. 1 (July 1991): 3–15. http://dx.doi.org/10.1079/bjn19910004.
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A diet questionnaire was developed in association with a computer program to provide rapid nutritional feedback to the general public. The questionnaire was validated against 16 d of weighed diet records and biochemical variables in blood and urine. The highest Pearson correlation coefficients obtained between the questionnaire and the weighed records were for alcohol, fibre, iron, riboflavin (r 0.74, 0.67, 0.66, 0.66 respectively). Striking sex differences were shown in the results; the trend for higher correlations persisted in females. At least 65% of subjects were classified by questionnaire to within one quintile of the classification by weighed record for the majority of nutrients.
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Song, Sihan, Hyeong-Gon Moon, Dong-Young Noh, So-Youn Jung, Eun Sook Lee, Zisun Kim, Hyun Jo Youn, et al. "Dietary Intake and Plasma Levels of Isoflavones Among Breast Cancer Survivors." Current Developments in Nutrition 4, Supplement_2 (May 29, 2020): 1490. http://dx.doi.org/10.1093/cdn/nzaa061_118.
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Abstract Objectives Isoflavones, rich in soybeans, are phytoestrogens with a similar chemical structure to estrogen and their roles in breast cancer prognosis remains equivocal. We aimed to estimate dietary intake of isoflavones and soy and examine their correlations with plasma levels of isoflavones among Korean breast cancer survivors. Methods A total of 974 female breast cancer survivors (mean age, 52 years) were included in the cross-sectional study. We estimated dietary intake of soy and isoflavones using either a 3-day food record (3DR; n = 645) or a food frequency questionnaire (FFQ; n = 329). Plasma isoflavone levels were measured by liquid chromatography methods in 439 participants. We calculated total isoflavones by summing daidzein, genistein, and glycitein. We estimated % contribution of food sources to dietary isoflavone intake and Pearson correlation coefficients with plasma isoflavone levels. We calculated de-attenuated correlations among those who reported dietary intake using 3DRs to reduce within-person variation (n = 233). Results The mean daily intake of total isoflavones among Korean breast cancer survivors was 21.91 mg/d. The major sources were tofu (% contribution = 30.6%), soybean (14.2%), and soybean sprouts (12.8%). The correlation coefficients with plasma isoflavone levels were 0.19 for dietary isoflavone intake and 0.18 for soy and its products intake. The de-attenuated correlation coefficients with plasma isoflavone levels were 0.25 for dietary isoflavone intake and 0.35 for soy and its products intake. When we examined the correlation between specific type of isoflavone and circulating level of each isoflavone, the de-attenuated correlation coefficients were 0.18 for daidzein, 0.28 for genistein, and 0.25 for glycitein. Conclusions We found the highest contribution from tofu and soybean to dietary isoflavone intake and moderate correlations of dietary intakes of soy and isoflavones with plasma levels of isoflavones among Korean breast cancer survivors. Our study warrants further investigation on the roles of isoflavones in breast cancer prognosis. Funding Sources This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (Ministry of Science and ICT, MSIT) (No. 2019R1F1A1061017).
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Owen, Robert J., Adam Z. Khan, Steven J. McAnany, Colleen Peters, and Lukas P. Zebala. "PROMIS correlation with NDI and VAS measurements of physical function and pain in surgical patients with cervical disc herniations and radiculopathy." Journal of Neurosurgery: Spine 31, no. 4 (October 2019): 519–24. http://dx.doi.org/10.3171/2019.4.spine18422.
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OBJECTIVEThe aim of this study was to compare the patient-reported outcome measures Neck Disability Index (NDI) and visual analog scale (VAS) with the Patient Reported Outcomes Measurement Information System (PROMIS) physical function (PF) and pain interference (PI) measures, respectively, and to determine their correlations in a surgical population longitudinally.Legacy outcome measures such as NDI and VAS are essential for analyzing treatments in spine surgery for cervical disc herniations with radiculopathy. Despite their usefulness, administrative burdens impose limits on completion of these measures. PROMIS was developed as a patient outcome measure in order to improve reporting of patient symptoms and function and to reduce administrative burden. Despite early positive results of PROMIS in orthopedics, NDI and VAS scores have not been compared with PROMIS scores in patients with cervical disc herniations with radiculopathy.METHODSEighty patients undergoing surgery for cervical disc herniations with radiculopathy were included. All patients were treated at the same tertiary spine center. Patients were seen and PROMIS PF and PI, NDI, and VAS arm and neck pain scores were collected preoperatively and at 1 year postoperatively. Correlations between NDI, VAS, and PROMIS PF and PI were quantified using Pearson correlation coefficients. Two-tailed Student t-tests were used to demonstrate correlation significance, with alpha = 0.05.RESULTSAll 80 (100%) patients completed all preoperative questionnaires. Fifty-seven (72%) and 75 (94%) patients completed all questionnaires at baseline and at the 6-month and 1-year follow-ups, respectively. PROMIS PF and NDI scores demonstrated a strong negative correlation, with Pearson r values of −0.81, −0.77, and −0.75 at baseline, 6 months, and 1 year. PROMIS PI and VAS neck pain scores demonstrated a moderately positive correlation, with Pearson r values of 0.51, 0.61, and 0.6. PROMIS PI and VAS arm pain scores demonstrated a moderately positive correlation, with Pearson r values of 0.46, 0.47, and 0.45.CONCLUSIONSPROMIS PF scores have a strong negative correlation with NDI scores at baseline and in the postoperative course in patients undergoing surgery for cervical disc herniations with radiculopathy. PROMIS PI scores have a moderately positive correlation with VAS neck and arm pain scores at baseline and in the postoperative course. Surgeons may factor these correlation results into the interpretation of patient-reported outcome measures in patients with cervical radiculopathy. Use of PROMIS PF and PI for this patient population may reduce administrative burden while providing reliable outcomes data.
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Hebert, James R., Prakash C. Gupta, Ramesh B. Bhonsle, Pesi N. Sinor, Hemali Mehta, and Fali S. Mehta. "Development and testing of a quantitative food frequency questionnaire for use in Gujarat, India." Public Health Nutrition 2, no. 1 (January 1999): 39–50. http://dx.doi.org/10.1017/s1368980099000051.
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AbstractObjective:To develop and test a quantitative, interviewer-administered food frequency questionnaire (FFQ) to ascertain nutrient intakes of individuals in northern India.Design:A 92-item FFQ was developed based on food use and market surveys of the study area. A validation study was conducted consisting of 24-h diet recalls (24HR) administered on 6 randomly selected days over 1 year. Two FFQs were administered, one each at the beginning and end of the 1-year period. FFQ and 24HR-derived nutrient scores were compared using correlation and regression analyses and by computing differences between nutrient intakes estimated by the two methods.Setting:Rural villages in Bhavnagar District, Gujarat, North India.Subjects:60 individuals who agreed to provide all necessary data.Results:Pearson (parametric) correlation coefficients averaged 0.69 in comparing nutrient scores derived from the 24HR with those from the first FFQ and 0.72 in comparing the second FFQ (P < 0.0001). Spearman correlation coefficients were virtually identical to the Pearson correlations, averaging 0.68 and 0.72, respectively. In regression analyses, most coefficients were close to 1.0 (perfect linear association). Nutrient scores were significantly and consistently higher on both FFQs relative to the 24HR.Conclusions:This FFQ produces results broadly comparable, and superior in some respects, to those commonly used in the West. Higher than average measures of association indicate its suitability for comparing exposures within this study population in reference to health-related endpoints.
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Wang, Hui-Min, and Sheng-Chieh Huang. "SDNN/RMSSD as a Surrogate for LF/HF: A Revised Investigation." Modelling and Simulation in Engineering 2012 (2012): 1–8. http://dx.doi.org/10.1155/2012/931943.
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Thousands of papers involved in heart rate variability (HRV). However, little was known about one important measure of HRV, the root mean square of successive heartbeat interval differences (RMSSDs). Another fundamental measure SDNN indicates standard deviation of normal to normal R-R intervals, where R is the peak of a QRS complex (heartbeat). Compared with SDNN, RMSSD is a short-term variation of heart rate. Through a time-frequency transformation, the ratio of low- and high-frequency power LF/HF represents the sympatho-vagal balance of the autonomic nervous system (ANS). Some research claimed that SDNN/RMSSD was a good surrogate for LF/HF. However, only two special cases supported this hypothesis in the literature survey. The first happened in resting supine state and the other was a group of prefrontal cortex patients. Both of their Pearson correlation coefficients reached 0.90, a reasonable criterion. In our study, a 6-week experiment was performed with 32 healthy young Asian males. The Pearson correlation coefficients had a normal distribution with average values smaller than 0.6 for 3 and 5-minute epochs, respectively. Our findings suggest this surrogate aspect could remain as a hypothesis.
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Tijerina, Alexandra, and Josep A. Tur. "Development and Validation of a Semiquantitative Food Frequency Questionnaire to Assess Dietary Intake in 40–65-Year-Old Mexican Women." Annals of Nutrition and Metabolism 76, no. 1 (2020): 73–82. http://dx.doi.org/10.1159/000506920.
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Background and Aims: Food frequency questionnaires (FFQ) have been widely used in epidemiologic studies since 1990s, but instruments need to be validated. The aim of this work was to create and assess the validity and reproducibility of an interview administered FFQ to be used in a Mexican women’s bone health cohort study, located in Monterrey city, Mexico. Methods: Validation of FFQ formed by 11 food groups and 136 food and beverage items was performed on 40–65-year-old Mexican women (n = 200) by applying 2 FFQ (test method) and six 24-h dietary recalls (24hR, reference method; 1 per season on weekdays and 2 on weekends). Pearson correlation coefficient was calculated of both logs, transformed intakes and energy-adjusted nutrient intakes based on the residual method, and intraclass correlation coefficients were calculated. Results: The relative validity of FFQ against the average of six 24hR for intakes of energy, macronutrients, cholesterol, water, vitamins and minerals required for bone metabolism such as vitamin D, calcium, magnesium, phosphorus were obtained. Pearson coefficients of correlation show significance (p < 0.05) for the validity, 0.244–0.820 and 0.258–0.794, for energy-unadjusted and adjusted data, respectively. Reproducibility coefficients range 0.186–0.810 for energy-unadjusted data and 0.174–0.597 for energy-adjusted data. Most nutrients showed lower than 5% of misclassification. Conclusion: The designed 136-item FFQ shows acceptable validity and reproducibility, and it is useful to be applied on 40–65-year-old Mexican women for the estimation of nutrient intakes in epidemiological studies.