Question 2. Having selected which of their compounds seems the most promising, the researchers also need to determine what effect (if any), long term treatment will have on muscle mass (a known side-effect of some types of anti-inflammatories is muscle wasting). 

Based on the following figure and details in the figure legend (figure 2), which statistical test should they use to compare these results and what is the conclusion on the effect on muscle mass?

FIGURE 2: Muscle mass as measured by DXA scan before and after treatment with compound determined in question 1. N = 10 mice.