Question

You are interested in finding a 95% confidence interval for the mean number of visits for physical therapy patients. The data below show the number of visits for 15 randomly selected physical therapy patients. Round answers to 3 decimal places where possible.

12

28

9

20

19

12

21

18

17

9

6

24

24

5

21

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

b. With 95% confidence the population mean number of visits per physical therapy patient is between  and   visits.

c. If many groups of 15 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.

Answer 1