2a A hospital administrator wants to measure average cost per stay in his institution. He is willing to be within $200 of the true value with a probability of 95 percent. An initial investigation of a random sample of 10 records determined that the standard deviation of cost was $3,987. How large a sample will need to be taken to meet the administrator's needs? 2b After learning of the size of sample needed in Exercise 2a, the administrator decided that he would be willing to be within $500. How big a sample does he need to reach this level of error?

Question reference from "Statistics for health care Management and administration" Textbook Chapter 7 exercise 7.5.2/7.5.3