In our study, “Interleukins 17 and 10 in a Sample of Egyptian Relapsing Remitting
Multiple Sclerosis Patients”, we adopted a well-organized statistical plan. The normality
testing, using Kolmogorov-Smirnov and Shapiro-Wilk test, was performed [
[1]
] using “SPSS Explore” procedure (Analyze → Descriptive Statistics → Explore → Plots → Normality plots with tests) [
[2]
]. The P value of K-S test of normality for all values was less than 0.05 and the same applied
for Shapiro-Wilk P value with positively skewed distribution on the histogram. In such non-normally
distributed sample, Mann-Whitney test (also called Mann–Whitney–Wilcoxon (MWW), or
Wilcoxon–Mann–Whitney test) was used [
[3]
] to compare results of unrelated (independent) groups, as the nonparametric counterpart
of the student's unpaired t-test, and Wilcoxon signed rank test was applied to compare the results of related
(dependent) samples (MS patients during relapse and in remission), as the nonparametric
counterpart of the student's paired t-test. The P-value shown in table comparing multiple sclerosis patients before and after relapse
is the value from Wilcoxon test.To read this article in full you will need to make a payment
Purchase one-time access:
Academic & Personal: 24 hour online accessCorporate R&D Professionals: 24 hour online accessOne-time access price info
- For academic or personal research use, select 'Academic and Personal'
- For corporate R&D use, select 'Corporate R&D Professionals'
Subscribe:
Subscribe to Journal of the Neurological SciencesAlready a print subscriber? Claim online access
Already an online subscriber? Sign in
Register: Create an account
Institutional Access: Sign in to ScienceDirect
References
- Investigation of four different normality tests in terms of type 1 error rate and power under different distributions.Turkish J. Med. Sci. 2006; 36: 171-176
- Statistical Analysis Quick Reference Guidebook with SPSS Examples.first ed. Sage Publications, London2007
- Wilcoxon-Mann-Whitney or t-test? On assumptions for hypothesis tests and multiple interpretations of decision rules.Stat Surv. 2010; 4: 1-39
- Individual comparisons by Ranking Methods.Biom. Bull. 1945; 1: 80-83
- On a test of whether one of two random variables is stochastically larger than the other.Ann. Math. Stat. 1947; 18: 50-60
Article info
Publication history
Published online: April 26, 2017
Accepted:
April 25,
2017
Received:
April 20,
2017
Identification
Copyright
© 2017 Published by Elsevier B.V.
