In: Statistics and Probability
Cholesterol (mg/dL) was measured in the same patients before and after taking drug D. Do a Wilcoxon signed-rank test for paired samples: state the null and (non-directional) alternative hypotheses, calculate (or bound) the p- value, and clearly state your conclusion for significance level ? = 0.05. The appropriate table is at the end of the quiz.
Before. After
200 250
190 245
180 175
190 188
180 500
200 260
190 260
190 230
a) Why would you do a Wilcoxon signed-rank test rather than a paired t-test?
b) Explain the difference between a paired sample and an unpaired sample.