The mean and the standard deviation of the sample of 65 customer satisfaction ratings are
=5.46 and s= 2.475
a. What does the histogram in Figure 2.16 say about whether the Empirical Rule should be used to describe the bank customer waiting times?
b. Use the Empirical Rule to calculate estimates of tolerance intervals containing 68.26 percent, 95.44 percent, and 99.73 percent of all possible bank customer waiting times.
c. Does the estimate of a tolerance interval containing 68.26 percent of all waiting times provide evidence that at least two- thirds of all customers will have to wait less than eight minutes for service? Explain your answer.

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