A cholesterol test was given to 10 heart patients with high cholesterol levels.The same 10 heart patients are then given a new cholesterol-reducing drug for six months.Before the patients begin taking the drug,they are told to maintain their current diets and eating habits so that the effect of the drug can be more effectively determined.After taking the drug for six months,the same patients are given a cholesterol test again.The pharmaceutical company manufacturing the medicine wants to know if the drug is effective in reducing the cholesterol levels of the patients.The cholesterol levels before and after taking the drug is recorded for each patient.Distribution of cholesterol level is not normally distributed.Which one of the following nonparametric tests is appropriate for this problem?
A)Wilcoxon signed rank test
B)Wilcoxon rank sum test
C)Sign test
D)Kruskal-Wallis test
E)Spearman's rank correlation test

Question

Quizplus · Accepted Answer

The Wilcoxon signed rank test is appropriate when the data is paired and not normally distributed. In this case, the before and after cholesterol levels are paired for each patient and the distribution of cholesterol level is not normally distributed. Therefore, the Wilcoxon signed rank test is the best choice for this problem. The other options are not appropriate for this problem. The Wilcoxon rank sum test is used for two independent samples, the sign test is used for dichotomous data, the Kruskal-Wallis test is used for comparing more than two independent samples, and Spearman's rank correlation test is used for measuring the strength of association between two variables.

A Cholesterol Test Was Given to 10 Heart Patients with High