Question: 36 A treatment trial is proposed to test the efficacy of vitamin E as a preventative agent for cancer. One problem with such a study is how to assess compliance among participants. A small pilot study is undertaken to establish criteria for compliance with the proposed study agents. In this study, 10 patients are given 400 IU/day of vitamin E and 10 patients are given similar-sized tablets of placebo over a 3-month period. Their serum-vitamin E levels are measured before and after the 3-month period, and the change (3-month baseline) is shown in Table 5.2

Suppose a change of 0.30 mg/dl in serum levels is proposed as a test criterion for compliance; that is, a patient who shows a change of greater than or equal to 30 mg/dl is considered a compliant vitamin-E taker. If normality is assumed, what percentage of the vitamin-E group would be expected to show a change of at least 0.30 mg/dl?