15-13. Cook-Rite Inc. has developed a spray product called No-Stick that it says prevents food from sticking to the cooking surface of frying pans.

Sixty pans of the same size, material, and make are to be tested (at the same heat setting) with No-Stick, with one half of the pan sprayed with No-Stick and the other half uniformly coated with margarine, where the side sprayed with No-Stick is determined in a random fashion.
No-Stick Food Sticking Food not Sticking Margarine Food Sticking 12 20 Food not Sticking 15 13 For α = 0.05, does No-Stick perform better than margarine?