Chapter 11 | Hypothesis Testing: Importance of Clinical Significance Initially, only 25 volunteers were available for each group. By the end of the month, however, there were 25,000 volunteers in each group, making this the largest (completely made up) clinical trial in history. Group treatment means and standard deviations are shown in the table to the right, for each week, as the number of participants increased. Both Cohen's d for a p-value are computed for the data from the first week. You might want to make sure you can repeat those. TABLE 11.3 1st Week 2nd Week 3rd Week 4th Week Sample size in each group (N) 25 250 2,500 25,000 Standard deviation in each group 20 20 20 20 Treatment 1 mean (placebo) 500 500 500 500 Treatment 2 mean (new drug) 501 501 501 501 Cohen's d 0.05 p-value 0.8604 a. Compute Cohen's d for each of the final three weeks. Which of the following graphs is correct for a plot of Cohen's d over all four weeks? i. Plot of Cohen's d Over Four-Week Period iii. Plot of Cohen's d Over Four-Week Period Graph A Graph C 0.06 0.05 0.04 Cohen's d 0.03 9 0.02 0.01 Week Week ii. Plot of Cohen's d Over Four-Week Period iv. Graph B Plot of Cohen's d Over Four-Week Period Graph D 0.06 0.05 0 . 6 0.04 Cohen's d 0.03 0.02 0.01 Week Week