An advertising executive wants to estimate the mean weeklyamount of time consumers spend watching traditional televisiondaily. Based on previous​ studies, the standard deviation isassumed to be 21 minutes. The executive wants to​ estimate, with​99% confidence, the mean weekly amount of time to within ± 6minutes.
a. What sample size is​ needed?
b. If​ 95% confidence is​ desired, how many consumers need tobe​ selected?
