The exercise data consist of the baseline and six-week (final) measures of quadriceps isometric force for 60 men aged 60 to 75 that were randomly assigned to either resistance only or running only exercise programs.

Variable	Description
Subj	Numeric code identifying subject
Group	0 = Running Only; 1 = Resistance Only
Bl_strength	Baseline leg strength in N-m
Final_strength	Final leg strength in N-m

Reference:

This data set is simulated. The study design is based on an unpublished study carried out at Creighton University in 2013.

1. Provide an appropriate graph to examine the distribution of baseline versus final leg strength for the two groups. What do you notice, is there a clear difference in the average leg strength increase for each group?
2. Write out the hypotheses appropriate for the following research question: is either exercise program more beneficial (in regards to leg strength) than the other?

(Hint: Create a new variable that is the difference between baseline and final strength. Then test for equality of means between groups.)

1. What is the conclusion of the hypothesis test?
2. What type of error might we have committed? Explain.
3. Based on the results of this hypothesis test, would you expect a confidence interval for the difference in average scores between groups to include 0? Explain your reasoning.