The June 2002 American Journal of Psychiatry reported that researchers used medication and psychotherapy to treat children aged 7 to 16 who exhibit bipolar symptoms. After 2 years, symptoms had cleared up in only 26 of the 89 children involved in the study.
a) Write a 95% confidence interval, and interpret it in this context.
b) If researchers subsequently hope to produce an estimate of treatment effectiveness for bipolar disorder that has a margin of error of only 6%, how many patients should they study?