Discussion:
Customers at the ASU bookstore spend varying amounts of money on "non-book" items. Historical data show that the amount spent per customer is normally distributed with a mean of $85 and a standard deviation of $30.
a. What proportion of customers spend at least $100 on non-book items?
b. If the proportion you found in part (a) above is considered on a "per customer" basis, it would represent the probability that any given customer spends at least $100. Round your estimate to the nearest 5%. If one check-stand at the store checks out 20 customers per hour, what is the probability that 10 or more of those 20 spend at least $100?