Two Population Means with Unknown Standard Deviations · Exercise 33

DIRECTIONS: For each of the word problems, use a solution sheet to do the hypothesis test. The solution sheet is found in Appendix E. 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.

At Rachel’s eleventh birthday party, eight girls were timed to see how long (in seconds) they could sit perfectly still in a relaxed position. After a two-minute rest, they timed themselves while jumping. The girls thought that the mean difference between their jumping and relaxed times would be zero. Test their hypothesis.

$$\begin{array}{cc}\text{Relaxed time (seconds)}& \text{Jumping time (seconds)}\\ \text{26}& \text{21}\\ \text{47}& \text{40}\\ \text{30}& \text{28}\\ \text{22}& \text{21}\\ \text{23}& \text{25}\\ \text{45}& \text{43}\\ \text{37}& \text{35}\\ \text{29}& \text{32}\end{array}$$

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

OpenStax, Statistics · §10.1 Two Population Means with Unknown Standard Deviations · Exercise 33