![Three runners on a track](images/runners.png)
It's four days after a major race, and you and your coworker at Athlete Testing Incorporated are informed that the first and second place athletes tested positive for doping. Abnormal levels of testosterone (a male sex hormone that acts as an anabolic steroid, building up muscles and bones) had been found in both of their urine samples when they were tested at the end of the race. The difficulty, however, comes in determining whether this testosterone is endogenous (produced naturally in the body) or exogenous (produced externally and taken as a drug).
Can you assume that the athletes have been taking exogenous testosterone (and were therefore doping) based on their higher than average testosterone counts?