The data set pef.dta contains data from a German study published in 2007 in the journal Pneumologie (61:83-85). The English translation of the title is, "Improvement in Expiratory Peak Flow (PEF) of COPD Patients due to "Lung" Sport for 12 Months." The data measures expiratory peak flow (PEF) from the lungs before and after 12 months. There were seven patients in the aerobic exercise group (beforeex, afterex) and 10 patients in a control group (beforecon and aftercon).

Datasheet link: https://docs.google.com/spreadsheets/d/1Kykr-DqBOmICvfv0rjIGx0xeqOSQTC_h59lMlspNm_U/edit?usp=sharing

Please check answers. If using statistical software, please provide step-by-step explanation. Please don't copy and paste from other sources. Thanks.

A. Perform a sign test on the exercise group. The p-value of the two-sided test is: 0.01563

Because p < .05, we can reject the null hypothesis and conclude that the true median difference is not the same.

B. Perform a sign test on the control group. The p-value of the two-sided test is: 0.3438

Because p > .05, we can fail to reject the null hypothesis conclude that the true median is the same for both groups.

C. Perform a Wilcoxon signed-rank test on the exercise group.

The Z score is 1.34 and the p-value is: 0.0233.

Because p < .05, we can reject the null hypothesis and conclude that there is a significant effect of exercise on expiratory peak flow.

D. Perform a Wilcoxon signed-rank test on the control group. The Z score is 1.99 and the p-value is 0.3428.

Because p < .05), we can reject the null hypothesis conclude that there is a significant effect of the control group on expiratory peak flow.

E. Use the percviner column to test the difference in the % increase between the control group and the exercise group. Perform a Wilcoxon rank sum test for the hypothesis test. The Z score is 2.70 and the p-value is 0.006787.

Because p < .05, we can conclude that there is a significant difference in percentage of control group and exercise group.