Treating Kidney Stones Researchers conducted a study to determine which of two

Chapter 4, Problem 14

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Treating Kidney Stones Researchers conducted a study to determine which of two treatments, A or B, is more effective in the treatment of kidney stones. The results of their experiment are given in the table. Treatment A Treatment B Total Effective 273 289 562 Not effective 77 61 138 Total 350 350 700 Source: C. R. Charig, D. R. Webb, S. R. Payne, and O. E. Wickham. Comparison of Treatment Real Calculi by Operative Surgery, Percutaneous Nephrolithotomi, and Extracorporeal Shock Wave Lithoripsy. British Medical Journal 292(6524): 879882. (a) Which treatment appears to be more effective? Why? The data in the table above do not take into account the size of the kidney stone. The data shown next indicate the effectiveness of each treatment for both large and small kidney stones. Small Stones Large Stones A BA B Effective 81 234 273 55 Not effective 6 36 77 25 (b) Determine the proportion of small kidney stones that were effectively dealt with using treatment A. Determine the proportion of small kidney stones that were effectively dealt with using treatment B. (c) Repeat part (b) for the large stones to create a conditional distribution of effectiveness by treatment for each stone size. (d) Draw a bar graph of the conditional distribution from part (c). (e) Write a short report detailing your findings.