Question: Economics and Finance ATM machines have made it easier and faster for customers to check account balances, transfer money, and obtain cash. Many banks are now considering the next generation of ATM machines, which will feature news headlines, full-motion video, and tickets to events. In a random sample of 500 customers, 280 said ATM machines should offer postage stamps.
a. Find the sample proportion of customers who believe ATM machines should offer postage stamps, and check the nonskewness criterion.
b. Find a 99% confidence interval for the true proportion of customers who believe ATM machines should offer postage stamps.
c. A bank official claims the proportion of customers who believe ATM machines should offer postage stamps is 0.60. Is there any evidence to refute this claim?