In a certain region, 22% of people over age 50 didn't graduate from high school. We would like to know if this percentage is the same among the 25-30 year age group.Use critical values to exactly 3 decimal places.

(a) How many 25-30 year old people should be surveyed in order to estimate the proportion of non-grads to within 9% with 98% confidence?

(b) Suppose we wanted to cut the margin of error to 7%. How many people should be sampled now?

(c) What sample size is required for a margin of error of 8%?