7. Designers of backpacks use exotic material such as supernylon Delrin, high-density polyethylene, aircraft aluminum, and thermomolded foam to make packs that fit comfortably and distribute weight to eliminate pressure points. The following data show the capacity

(cubic inches), comfort rating, and price for 10 backpacks tested by Outside Magazine.

Comfort was measured using a rating from 1 to 5, with a rating of 1 denoting average comfort and a rating of 5 denoting excellent comfort (Outside Buyer’s Guide, 2001).

a. Determine the estimated regression equation that can be used to predict the price of a backpack given the capacity and the comfort rating.

b. Interpret b1 and b2.

c. Predict the price for a backpack with a capacity of 4500 cubic inches and a comfort rating of 4.