Additional Information and Full Hypothesis Test Examples · Exercise 45

For each of the word problems, use a solution sheet to do the hypothesis test. The solution sheet is found in Appendix E, Solution Sheets. Please feel free to make copies of the solution sheets. For the online version of the book, it is suggested that you copy the.doc or the.pdf files.

Previously, an organization reported that teenagers spent 4.5 hours per week, on average, on the phone. The organization thinks that, currently, the mean is higher. Fifteen randomly chosen teenagers were asked how many hours per week they spend on the phone. The sample mean was 4.75 hours with a sample standard deviation of 2.0. Conduct a hypothesis test.
At a significance level of a = 0.05, what is the correct conclusion?

(a) There is enough evidence to conclude that the mean number of hours is more than 4.75.
(b) There is enough evidence to conclude that the mean number of hours is more than 4.5.
(c) There is not enough evidence to conclude that the mean number of hours is more than 4.5.
(d) There is not enough evidence to conclude that the mean number of hours is more than 4.75.

This exercise builds on another exercise in its source book, which isn't shown here.

OpenStax, Statistics · §9.5 Additional Information and Full Hypothesis Test Examples · Exercise 45