Suppose that in a random sample of 55 baseball pitchers, 8 are left handed

Suppose that in a random sample of 55 baseball pitchers, 8 are left handed. a. Using the random sample, build a confidence interval for the proportion of left-handed baseball pitchers with confidence level 90%. b. Suppose you know for sure that no less than 70% of baseball pitchers are right handed (assume that each baseball pitcher is either left handed or right handed). You want to sample additional players so that the width of the confidence interval at a 95% confidence level is no larger than 0.03. How many additional baseball pitchers should you sample?