In a study of government financial ald for college students, It becomes nocessary to estimate the percentage of full-time college students who earn a bachelor's degree in four years or less. Find the sample size needed to estimate that percentage. Use a 0.04 margin of error and use a confidence lovel of 95%. Completo parts (a) through (c) below. a. Assume that nothing is known about the percentage to be estimated n= b. Assume prior studies have shown that about 40% of full-time students carn bachelor's degrees in four years or less. n= c. Does the added knowledge in part (b) have much of an effect on the sample size?​