1. [6 points] Refer to the dataset "cyclosporine.xlsx". This dataset presents data from 17 participants, 7 of whom were given cyclosporine, an immunosuppressant, as part of an organ transplant, and 10 of whom were given a different drug. Researchers were interested in the impacts of long-term cyclosporine use on renal function. To help answer this question, researchers measured the serum creatinine levels present in participants given cyclosporine and given another drug. Variables in this data include: IDnum: Participant ID (1 to 17) cyclosporine: Indicator of cyclosporine use (0 for other drug, 1 for cyclosporine) creatinine: Participant serum creatinine level (mg/dL) systolic: Participant systolic blood pressure level (mmHg) Question modeled from: Palestine et al., "Renal Histopathologic Alterations in Patients Treated with Cyclosporine for Uveitis" - NEJM (1986) 1a. [2 points] Researchers wish to compare serum creatinine levels between cyclosporine users and non-users. To help them, explore the distributions of serum creatinine levels in the two treatment groups with two side-by-side boxplots. Give a brief written summary comparing the two boxplots. Comments: Your graphs should be descriptive, organized and clear. Think carefully about labeling, clarity and communication. Your reader should be able to compare, at a glance, the serum creatinine distributions for the two treatment groups. Graphing is more than the mechanics of the software; you must communicate a story accurately and succinctly to address the interests of the investigators. 1a. ANSWER: 1b. [1 point] Based on your answer to (1a), do you think it is appropriate to compare average serum creatinine levels between the two treatment groups using a two-sample t-test? If so, why? If not, why not? 1b. ANSWER: 1c. [3 points] Regardless to your answer in (1b), carry out Wilcoxon Rank sum test to compare the serum creatinine levels betweenRegardless to your answer in (1b), carry out Wilcoxon Rank sum test to compare the serum creatinine levels between treatment groups. Complete all the usual steps of hypothesis testing such as: State the null and alternative hypothesis. Check any assumptions required for your proposed test. Explain briefly. State W and calculate the test-statistic. Show a few interim steps, as practical. Calculate the p-value. State the degrees of freedom, if appropriate. If you use software, state the command you used and/or include a portion of the output. If you used table, state that. Interpret the p-value for a non-statistician in the context of the problem. [The p-value is a probability What is it the probability of in THIS problem? Do NOT use the words \"null hypothesis."] Do NOT simply state whether or not the result is statistically significant. What {if anything) can we conclude about serum creatinine levels in the two treatment groups? 2. [7.5 points] A weight management program assigned 300 overweight and obese women of child-bearing age to either an exercise-based intervention or a control condition. The women were followed over a period of time, and were measured after 3 months. The results are displayed in the table below: Not obese 55 _ 2a. [2 points] Calculate the risk ratio of obesity associated with being in the control group. Interpret the results. 2a. ANSWER: 2b. [4 points] Calculate the odds ratio and the corresponding 95% confidence interval associated with obesity in the control group. Interpret both the results in plain, non-statistical language for a person who has not had a statistics course 2b. ANSWER: 2c. [1.5 points] Assume that the 95% CI that you computed in the above question contains one. Your colleague looks at the results and is disappointed. He/she/ states "I really thought that this intervention would be effective. Our study just showed that the odds of obesity are the same in the control and intervention groups. How disappointing.\" Is your colleague correct? Why or why not? Explain briefly how you would respond to these statements.