In a study to investigate the effect of regular exercise on raising HDL (good cholesterol) levels, a random sample of five male subjects known to have low HDL levels had their HDL measured. After six months on a regular exercise schedule, it was measured again. The data are given in the following table. How do you know that the data should be analyzed using the Wilcoxon signed rank test?
A)There are three groups, and some of the observations are negative numbers.
B)There are three groups, with one observation in each group matched to a subject.
C)There are two groups, and some of the observations are negative numbers.
D)There are two groups, with one observation in each group matched to a subject.

Question

In a study to investigate the effect of regular exercise on raising HDL (good cholesterol) levels, a random sample of five male subjects known to have low HDL levels had their HDL measured. After six months on a regular exercise schedule, it was measured again. The data are given in the following table.  How do you know that the data should be analyzed using the Wilcoxon signed rank test?
A)There are three groups, and some of the observations are negative numbers. 
B)There are three groups, with one observation in each group matched to a subject. 
C)There are two groups, and some of the observations are negative numbers. 
D)There are two groups, with one observation in each group matched to a subject.

Quizplus · Accepted Answer

The data only have two groups (before and after exercise) and the observations within each group are matched to the same subject, indicating a paired design. Therefore, the appropriate test to use is the Wilcoxon signed rank test, which is designed for paired data.

In a Study to Investigate the Effect of Regular Exercise