After the pilot study describes in Problem 2, the main trial is conducted and in
ID: 2960287 • Letter: A
Question
After the pilot study describes in Problem 2, the main trial is conducted and involves a total of 200 patients. Patients are enrolled and randomized to receive either the experimental medication or placebo. The data shown in table 6-7 are data collected at the end of the study after 6 weeks on the assigned treatment. Generate a 95% confidence interval for the difference in proportions of patients withe hypertension between groups.Baseline 120 145 130 160 152 142 126 121 115 135
4 Weeks 122 142 135 158 155 140 130 120 124 130
Table 6-7
Data for Problem 3
Experimental n=100 Placebo n=100
% Hypertensive 14% 22%
Explanation / Answer
Group Baseline 4 Weeks Mean 134.60 135.60 SD 14.86 13.18 SEM 4.70 4.17 N 10 10 standard error of difference = 1.366 df = 9 The mean of Baseline minus 4 Weeks equals -1.00 So 95% confidence interval of this difference: From -4.09 to 2.09