12.6 Fast food and indigestion Let y = number of times fast food was eaten in the past month and x = number of times indigestion happened in the past month, measured for all students at your school. Explain the mean and variability aspects of the regression model my = a + bx in the context of these variables. In your answer, explain why

(a) it is more sensible to use a straight line to model the means of the conditional distributions rather than individual observations and

(b) the model needs to allow variation around the mean.