Question: Distribution of the residuals. Some statistical methods require that the residuals from a regression line have a Normal distribution. The residuals for the nonexercise activity example are given in Exercise. Is their distribution close to Normal? Make a Normal quantile plot to find out.
Exercise: Find the sum of the residuals. Here are the 16 residuals for the NEA data rounded to two decimal places:
0.37 -0.70 0.10 -0.34 0.19 0.61 -0.26 -0.98
1.64 -0.18 0.23 0.54 -0.54 -1.11 0.93 -0.03
Find the sum of these residuals. Note that the sum is not exactly zero because of roundoff error.