13.3 Predicting visitor satisfaction For all the restaurants in a city, the prediction equation for y = average monthly visitor satisfaction rating (range 0–4.0 where 0 =

very poor and 4 = very good) and x1 = the monthly food quality score given by the food inspection authority

(range 0–4.0 where 0 = very poor and 4 = very good) and x2 = the number of visitors in a month is yn = 0.35 + 0.55x1 + 0.0015x2.

a. Find the predicted average monthly visitor satisfaction rating for a restaurant having (i) a monthly food quality score of 4.0 and 800 visitors in a month and (ii) a monthly food quality score of 2.0 and 200 visitors in a month.

b. For restaurants with x2 = 500, show that yn = 1.10 + 0.55x1.

c. For restaurants with x2 = 600, show that yn = 1.25 + 0.55x1. Thus, compared to part

b, the slope for x1 is still 0.55, and increasing x2 by 100

(from 500 to 600) shifts the intercept upward by 100 * 1slope for x22 = 10010.00152 = 0.15 units.