Anabolic steroid abuse has been increasing despite increased press reports of adverse medical and psychiatric consequences. In a recent study, medical researchers studied the potential for addiction to testosterone in hamsters (Neuroscience [2004]: 971–981).

Hamsters were allowed to self-administer testosterone over a period of days, resulting in the death of some of the animals. The data below show the proportion of hamsters surviving versus the peak self-administration of testosterone (mg). Fit a logistic regression equation and use the equation to predict the probability of survival for a hamster with a peak intake of 40mg.

Peak Intake

(micrograms)

Survival Proportion

(p)

p 1 2 p yr 5 lna p 1 2 p b

10 0.980 49.0000 3.8918 30 0.900 9.0000 2.1972 50 0.880 7.3333 1.9924 70 0.500 1.0000 0.0000 90 0.170 0.2048 1.5856