Two Means - Matched Pairs (Dependent Samples): Videos & Practice Problems

A nutritionist wants to test whether a new diet affects cholesterol levels. She measures the cholesterol of $13$ participants before and after following the diet for $8$ weeks. The differences are computed as 'after minus before.' The normal probability plot of the differences yields a correlation coefficient of $0.945$. The critical value for $n=13$ at $\alpha =0.05$ is $0.917$. Based on this information, is it reasonable to assume the differences are normally distributed?