(b) The slope means that for each cup of coffee, there’s a reduction of 1.52 complaints. This implies that for every two cups of coffee there are about three fewer complaints.
(c) There will be about 13 complaints (12.75 in the model) if he doesn’t drink any coffee.
(d) The complaints drop below zero if he drinks 9 cups of coffee. The model goes negative, so perhaps he gets compliments instead of complaints!
(e) Yes, this is reasonable, because the model predicts no complaints if he drinks 8 or 9 cups of coffee.
(f) P(n)=0, n=12.75/1.52=8.4 cups.