(2) I should’ve gone into the social sciences. I think I could’ve made a very fulfilling career of breast-related sociological studies. I consider myself something of a connoisseur.
(3) Maybe large-breasted waitresses make the dining experience more enjoyable. The fact that it is appearance-related does not mean that the tip was not related to the enjoyability of the outing. He should do a study of wife’s breast-size and its relation to male marital happiness.
(4) The author suggests a uniform tip. As one would expect from a liberal, he does not indicate whether the purpose is to help the small-breasted, or hurt the large-breasted. Maybe a federally subsidized waitress implant program would be more beneficial.
That's a far more complex social interraction and not subject to a straight-forward test. Part of what these studies do is they attempt to boil away all other factors to test for just one thing. It's not always possible.
Here we have a social interaction between people that we don't expect to know eachother on a personal-level: the customer & the waitress. AND we have a handy measuring-stick -- the size of the tip. Reading how these studies are constructed can be pretty interesting stuff.