Prepare the 95% confidence interval for average waiting time...

mean = 19.8

standard deviation = 2.06 minutes

sample / n = 100

95% confidence interval = 1.96

standard error = 2.06/sqrt 100 = 2.06/10 = .206

19.8 +/- 19.96 (.206)

19.8 +/- 0.40376

19.39 less than or equal to u less than or equal to 20.20

Jones Bank can be 95% confident that the average waiting time for customers is between 19.39 and 20.20