7.38.

Michael Gordon, a professional basketball player, threw 200 penalty shots and scored 174 of them.

a) Estimate the standard error of the ratio of all the shots that Michael fails.

b) Build a confidence interval of 98% for the proportion of all penalty shots that Michael fails.

7.39.

SnackMore recently surveyed 95 consumers and found that 80% purchased SnackMore fat-free cookies each month.

a) Estimate the standard error of the ratio.

b) Construct a 95% confidence interval for the true proportion of people who buy cookies each month.