3. It can be shown that the sum of the residuals from a least squares regression line always equals zero. a) Does it follow from this fact that the mean of the residuals must equal zero? A. Yes B. No b) Does it follow from this fact that the median of the residuals must equal zero - yes or no? A. Yes B. No This question should be very easy for all students, but some struggle. The question b sum of values equals zero, does the mean have to equal zero, and does the median have t answer is yes to the first, because the mean is calculated as the sum divided by the n