A random sample of 441 shoppers revealed that 76% made at least one purchase at a discount store last month.
a. Based on this sample information, what is the 90% confidence interval for the population proportion of shoppers who made at least one discount store purchase last month?
b. The city of San Luis Obispo, California, has a population of 35,000 people. Referring to part a, determine a 90% confidence interval for the number of shoppers who made at least one discount store purchase last month.