Find the probabilities that customers of the bank in Example 7.1 take:

(a) Less than 12 seconds

(b) Less than 15 seconds

(c) Less than 18 seconds

(d) Less than 21 seconds

(e) Less than 24 seconds to use the cash dispensing machines.

You can do this by listing these values in a column in the MINITAB worksheet and specifying the mean, 18, the standard deviation, 3, and the column location of the values, in the command window of the Normal option from the Probability Distributions submenu of the Calc menu. You should get the following results.