Leaking tanks: Leakage from underground fuel tanks has been a source of water pollution. In a random sample of 107 gasoline stations, 18 were found to have at least one leaking underground tank.

a. Find a point estimate for the proportion of gasoline stations with at least one leaking underground tank.

b. Construct a 95% confidence interval for the proportion of gasoline stations with at least one leaking underground tank.

c. Use the point estimate computed in part

(a) to determine the number of stations that must be sampled so that a 95% confidence interval will have a margin of error of 0.03.