Solve the following problem:
Q: a) Consider the population of Wisconsin licensed drivers aged 20 or younger. A random sample of size 363 from this population is obtained. Fifty three (53) of these people state that they drink alcoholic beverages 'several times a week'. Find a 98% confidence interval for the proportion in the entire population who drink 'several times a week'.
b) A bank believes that approximately 25% of its checking account customers have used at least one other service provided by the bank during the last six months. How large a sample will be needed to estimate the true proportion to within 0.10 at the 99% level of confidence?