Statistical Comments on "Assessment of Musculoskeletal Strength and Levels of Fatigue During Different Phases of Menstrual Cycle in Young Adults"

Farrokhi, Mehrdad; Amani-Beni, Ali

doi:10.7860/jcdr/2017/29359.10319

Cited by 3 publications

(3 citation statements)

References 1 publication

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“…One-way ANOVA is used to determine significant differences between two or more unrelated (independent) groups [5][6][7]. Based on the design of this study, the authors must use repeated measures ANOVA or the Friedman test to compare serum levels of 25 (OH)D and EBNA-1 between different months of measurement [8][9][10]. Moreover, to compare mean values of 25(OH) D and EBNA-1 between each 2 months, they must use the Wilcoxon signed rank test or the paired t-test.…”

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confidence: 99%

Seasonal variation of vitamin D and Epstein−Barr virus antibody in multiple sclerosis patients

Farrokhi

2018

Euro J of Neurology

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confidence: 99%

Seasonal variation of vitamin D and Epstein−Barr virus antibody in multiple sclerosis patients

Farrokhi

2018

Euro J of Neurology

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“…4,[7][8][9][10] Taken together, we believe that most of the statistical tests used in this study (including Student t-test and Mann-Whitney test) are inappropriate, and the authors' valuable study could be better used as citable experimental evidence if analyzed with appropriate statistical tests (including dependent t-test or Wilcoxon signed rank test).…”

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confidence: 96%

Statistical comments on “Antiretroviral changes during the first year of therapy”

Peykanpour

Ansaripour

Ebrahimi

2018

Rev. Assoc. Med. Bras.

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We read with great interest a recent article by Bandeira et al.1 entitled "Antiretroviral changes during the first year of therapy." In this study, the authors investigated the first year of highly active antiretroviral therapy (HAART) in patients from a reference center on HIV/AIDS management in Fortaleza. They evaluated CD4 T lymphocyte (LTCD4) count and viral load (VL) over the course of the treatment (4 time-points of measurement including before treatment, 2-4 months, 5-8 months and 9-12 months). As stated in the methods section and chart 1 of the article, the authors used Student t-test (independent t-test) and Mann-Whitney test for comparison of LTCD4 count and VL between different time-points of measurement. Indeed, the authors investigated levels of the numerical variables in one sample of the patients in different times and assumed them as independent measurements. Since they used only one sample of the patients and measured numerical variables in them during different timepoints, their measurement are dependent. Student t-test and Mann-Whitney test are used to compare the differences between the means of two independent (unrelated) groups, but the measurements of the mentioned study are not independent.2-6 Therefore, after assessment of the normal distribution of the variables, due to dependence of measurements, they must use dependent t-test (paired t test) or Wilcoxon signed rank test for comparisons between different time-points of measurement. 4,[7][8][9][10] Taken together, we believe that most of the statistical tests used in this study (including Student t-test and Mann-Whitney test) are inappropriate, and the authors' valuable study could be better used as citable experimental evidence if analyzed with appropriate statistical tests (including dependent t-test or Wilcoxon signed rank test).

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“…ANOVA and Kruskal-Wallis test are used for comparison of the means of more than 2 independent groups (Gaddis 1998; Farrokhi 2017b; Farrokhi and Arjaki 2017; Farrokhi and Peykanpour 2017b). Therefore, after assessment of the normal distribution of studied quantitative variables, including concentrations of plasma osmolality, TEAC, and FRAP, the authors must use repeated-measures ANOVA or Friedman test for comparison of the means of each variable at pre-exercise, immediately postexercise, and 1 h after full rehydration (Farrokhi 2017a;Farrokhi and Amani-Beni 2017). Furthermore, they must use Wilcoxon test and paired t test for comparison of concentrations of plasma osmolality, TEAC, and FRAP between 2 time-points of measurement.…”

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confidence: 99%

Discussion of “Effect of exercise-induced dehydration on circulatory markers of oxidative damage and antioxidant capacity”

Zahedi

Amani-Beni

2018

Appl. Physiol. Nutr. Metab.

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We read with great interest a recent article by Georgescu et al. (2017) entitled "Effect of exercise-induced dehydration on circulatory markers of oxidative damage and antioxidant capacity". The authors aimed to investigate effects of hydration and rehydration by using sensitive indirect measures of oxidative stress and the antioxidant capacity response. In this study, they evaluated concentrations of plasma osmolality, Trolax equivalent antioxidant capacity (TEAC), and ferric reducing ability of plasma (FRAP) in a sample of athletes during pre-exercise, immediately postexercise, and 1 h after full rehydration. As stated in statistical analysis and also abstract of the article, the authors used 1-way ANOVA to compare differences in means of numerical variables (i.e., concentrations of plasma osmolality, TEAC, and FRAP) of different timepoints of measurement. Since they investigated the same sample of participants in each group during different time-points (i.e., pre-exercise, immediately postexercise, and 1 h after full rehydration), their measurements are completely dependent (Farrokhi and Peykanpour 2017a;Farrokhi and Shirian 2017;. ANOVA and Kruskal-Wallis test are used for comparison of the means of more than 2 independent groups (Gaddis 1998; Farrokhi 2017b; Farrokhi and Arjaki 2017; Farrokhi and Peykanpour 2017b). Therefore, after assessment of the normal distribution of studied quantitative variables, including concentrations of plasma osmolality, TEAC, and FRAP, the authors must use repeated-measures ANOVA or Friedman test for comparison of the means of each variable at pre-exercise, immediately postexercise, and 1 h after full rehydration (Farrokhi 2017a;Farrokhi and Amani-Beni 2017). Furthermore, they must use Wilcoxon test and paired t test for comparison of concentrations of plasma osmolality, TEAC, and FRAP between 2 time-points of measurement. Conflict of interest statementThe authors declare that they have no conflict of interest. 258-265. doi:10.1111/j.1553-2712.1998.tb02624.x. Georgescu, V.P., de Souza Junior, T.P., Behrens, C., Barros, M.P., Bueno, C.A., Utter, A.C., et al. 2017. Effect of exercise-induced dehydration on circulatory markers of oxidative damage and antioxidant capacity. Appl. Physiol. Nutr. Metab. 42(7): 694-699. References

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Statistical Comments on "Assessment of Musculoskeletal Strength and Levels of Fatigue During Different Phases of Menstrual Cycle in Young Adults"

Cited by 3 publications

References 1 publication

Seasonal variation of vitamin D and Epstein−Barr virus antibody in multiple sclerosis patients

Seasonal variation of vitamin D and Epstein−Barr virus antibody in multiple sclerosis patients

Statistical comments on “Antiretroviral changes during the first year of therapy”

Discussion of “Effect of exercise-induced dehydration on circulatory markers of oxidative damage and antioxidant capacity”

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