Question

You are interested in finding a 98% confidence interval for the average commute that non-residential students have to their college. The data below show the number of commute miles for 13 randomly selected non-residential college students.

28

12

25

14

15

12

5

18

28

7

6

18

24

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

b. With 98% confidence the population mean commute for non-residential college students is between  and   miles.

c. If many groups of 13 randomly selected non-residential college students are surveyed, 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 commute miles and about  percent will not contain the true population mean number of commute miles.

Answer 1

a.Since In this question the sample size is 13 which is less than 30 and population standard deviation is unknown then we will use t distribution to get the confidence interval for this problem.

b. In this question it has been given that,

n = 13,

Level of significance = 2%

Sample mean =

16.30769

Standard deviation =

8.055894

Note: Values of mean and standard deviation of data has been calculated by using the Excel. In data we have to select the whole range

c.About 98% of these confidence intervals will contain the true population mean number of commute miles and about 2% percent will not contain the true population mean number of commute miles.