Wilcoxon Rank-Sum Test. In Exercises 5–8, use the Wilcoxon rank-sum test.
7. Clinical Trials of Lipitor The sample data below are changes in LDL cholesterol levels in clinical trials of Lipitor (atorvastatin). It was claimed that Lipitor had an effect on LDL cholesterol. (The data are based on results given in a Parke-Davis memo from David G. Orloff, M.D., the medical team leader for clinical trials of Lipitor. Pfizer declined to provide the author with the original data values.) Negative values represent decreases in LDL cholesterol. Use a 0.05 significance level to test the claim that for those treated with 20 mg of Lipitor and those treated with 80 mg of Lipitor, changes in LDL cholesterol have the same median. What do the results suggest?
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ELEMENTARY STATISTICS WITH MYSTATLAB
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- 1.“Effects of Short-Term Supplementation with Selenised Yeast on Milk Production and Composition of Lactating Cows”(Australian Journal of Dairy Technology, [2004]: 199-203) supplied the following data on milk selenium concentration (mg/L) for a sample of cows given seleniumsupplement (the treatment group) and a sample of cows given no supplement (the control group). The measurements of selenium were taken initally and again after a 9-day period. The study was conducted becausea deficiency of the trace element selenium in the diet can negatively impact growth, immunity, muscle and neuromuscular function, and fertility. The production of selenium supplements to dairy cows is justified when pastures have low selenium levels. data is attached a.Use the given data for the treatment group to determine if there is sufficient evidenceto conclude that the mean selenium concentration is greater after 9 days of the selenium supplement. b.Are the data for the cows in…arrow_forwardHerbal cancer A report in the New England Journal of Medicine notes growing evidence that the herb Aris-tolochia fangchi can cause urinary tract cancer in those who take it. Suppose you are asked to design an experi-ment to study this claim. Imagine that you have data on urinary tract cancers in subjects who have used thisherb and similar subjects who have not used it and thatyou can measure incidences of cancer and precancerouslesions in these subjects. State the null and alternativehypotheses you would use in your study.arrow_forwardLobbying Congress. In the special report, “Bitter Pill: Why Medical Bills Are Killing Us” (TIME, Vol. 181, No. 8, 2013), S. Brill presented an in-depth investigation of hospital billing practices that reveals why U.S. health care spending is out of control. One of the many statistics provided in the report is that, during the period from 1998 through 2012, the pharmaceutical and health-care-products industries and organizations representing doctors, hospitals, nursing homes, health services, and HMOs spent $5.36 billion lobbying Congress. a. Under what conditions would the $5.36 billion lobbyingexpenditure figure be a descriptive statistic? Explain your answer. b. Under what conditions would the $5.36 billion lobbyingexpenditure figure be an inferential statistic? Explain your answer.arrow_forward
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