A researcher wants to determine a 95% confidence interval

4. A researcher wants to determine a 95% confidence interval for the mean number of hours that UMKC studentsspend doing homework per week. Suppose she knows that the standard deviation for hours spent per weekby all UMKC students doing homework is 7. She allows the estimate to be within 1.5 hours of the populationmean.
(a) What is the maximum error of estimate she allows?
(b) How large a sample should the researcher select so that the estimate will be within 1.5 hours of the population mean?