You are interested in finding a 98% confidence interval for the mean number of visits for physical therapy patients. The data below show the number of visits for 11 randomly selected physical therapy patients.

22

23

20

6

19

18

15

26

18

7

23

a. To compute the confidence interval use a ? z t distribution.

b. With98% confidence the population mean number of visits per physical therapy patient is between and visits.

c.If many groups of 11 randomly selected physical therapy patients are studied, then a different confidence interval would be produced from each group. About percent of these confidence intervals will contain the true population mean number of visits per patient and about percent will not contain the true population mean number of visits per patient.