Body Weight and the Maximum of Effort

Using a modified Skinner-box, we try to find out, by working with 24 Albino-cross-Hooded rats, whether there exist some kind of relation between body weight and max. of effort. All subjects were grown in laboratory in the Psychology Department National Taiwan University and their average age was 150 days when the experiment began. And there is the result: (1) There are two kinds of bar pressing, namely: usual way of bar pressing and particular way of bar pressing. (2) Counting the two kinds as one, we have coefficient r= -0.014 for body weight and max. of effort. However, if we leave those special ones alone and take only the usual ones, which holds 83.33% of subjects, we gain another r'=0.87 with Z=3.83. The conclusion is that the body weight, in general, correlate greatly witl max. of effort.