13. A psychologistwants to estimate , the mean IQ of the students of a university. To do...

13. A psychologistwants to estimate μ, the mean IQ of the students of a university. To do so, she takes a sample of size n of the students and measures their IQ’s. Then she finds the average of these numbers. If she believes that the IQ’s of these students are independent random variables with variance 170, using the central limit theorem, how large a sample should she choose to be 98% sure that her average is accurate within ±0.2?