A pharmaceutical company wishes to test a new drug with the expectation of lowering cholesterol levels. Ten subjects are randomly selected and their cholesterol levels are recorded. The results are listed below. The
Subjects were placed on the drug for a period of 6 months, after which their cholesterol levels were tested
Again. The results are listed below. (All units are milligrams per deciliter.)Use the Wilcoxon signed-rank test to
Find the test statistic $\mathrm { W } _ { \mathrm { S } }$ to test the companyʹs claim that the drug lowers cholesterol levels. $$\begin{array} { l c c c c c c c c c c }
\hline \text { Subject } & 1 & 2 & 3 & 4 & 5 & 6 & 7 & 8 & 9 & 10 \
\hline \text { Before } & 219 & 245 & 253 & 200 & 244 & 243 & 238 & 197 & 227 & 224 \
\text { After } & 204 & 240 & 261 & 190 & 239 & 243 & 208 & 179 & 225 & 209
\end{array}$$

Question

A pharmaceutical company wishes to test a new drug with the expectation of lowering cholesterol levels. Ten subjects are randomly selected and their cholesterol levels are recorded. The results are listed below. The
Subjects were placed on the drug for a period of 6 months, after which their cholesterol levels were tested
Again. The results are listed below. (All units are milligrams per deciliter.)Use the Wilcoxon signed-rank test to
Find the test statistic $\mathrm { W } _ { \mathrm { S } }$ to test the companyʹs claim that the drug lowers cholesterol levels. $$\begin{array} { l c c c c c c c c c c } 
\hline \text { Subject } & 1 & 2 & 3 & 4 & 5 & 6 & 7 & 8 & 9 & 10 \
\hline \text { Before } & 219 & 245 & 253 & 200 & 244 & 243 & 238 & 197 & 227 & 224 \
\text { After } & 204 & 240 & 261 & 190 & 239 & 243 & 208 & 179 & 225 & 209
\end{array}$$

Quizplus · Accepted Answer

The Wilcoxon signed-rank test statistic is calculated as the sum of the ranks of the positive differences between the before and after cholesterol levels. In this case, the positive differences are: 15, 5, 8, 10, 5, 0, 30, 18, 2, 15. The ranks of these differences are: 1, 2, 3, 4, 2, 1, 5, 3, 1, 2. The sum of these ranks is 24, which is the test statistic.

A Pharmaceutical Company Wishes to Test a New Drug with the Expectation