Question

A is TRUE for a Wilcoxon’s rank-sum test. B is FALSE for a repeated measures t-test.

		A: Assumes that the data is skewed. B: Does not require assumptions of normality.
		A: Sample variance is used to estimate population variance. B: Assumes the data is skewed.
		A: Ranking reduces the effects of extreme outliers. B: Assumes the use of only interval scales.
		A: Does not require assumptions of normality. B: Sample variance is used to estimate population variance.

Answer 1

1st option is false because no assumption of skewness is done in wilcocons rank sum test and t-test cannot be conducted if the observations are not normally distributed

2nd option is false because Wilcoxon rank sum test does not estimate population variance and also repeated measures t-test has the assumption of normality and hence data cannot be skewed

3rd option is also false. Repeated-measures t-tests is conducted on continuous observations of an outcome that are normally distributed. And hence ' Assumes the use of only interval scales.' is false.

4th option is correct as Wilcoxon rank sum test is a non-parametric test that does not require assumption of normality and in repeated measures t-test, Sample variance is used to estimate population variance. Both statements are true