The size of Xs is related to the variability of scores in the population and to the sample

A rat presses a bar when a light is on but not when it is off because in the past a

bar press has been reinforced when the light was on but not when it was off. The light is a/an (a) reinforcer (b) positive reinforcer (c) negative reinforcer (d) partial reinforcer (e) discriminative stimulus

Vanessa is terrified of becoming fat. Her weight is normal, and most of the time she has normal eating habits, but sometimes she loses control and "binges" on large amounts of food In an effort to avoid becoming fat, Vanessa makes herself throw up after these binges. Vanessa is exhibiting symptoms of ___________.

a. bulimia b. anorexia nervosa c. pica d. the secular trend