Veterinarians suspect that enteroliths (calcifications in the gut of horses) are related to diet-in particular, alfalfa. To investigate this suspicion, a group of veterinarians collected information on the diet of horses and whether the horses developed enteroliths. The table below displays the findings (a case is a horse with enteroliths, a control is without enteroliths). The probability that a randomly selected horse has enteroliths, given that it is fed more than 50% alfalfa, is:
A)0.23.
B)0.348.
C)0.08.
D)0.2.

Question

Veterinarians suspect that enteroliths (calcifications in the gut of horses) are related to diet-in particular, alfalfa. To investigate this suspicion, a group of veterinarians collected information on the diet of horses and whether the horses developed enteroliths. The table below displays the findings (a case is a horse with enteroliths, a control is without enteroliths).  The probability that a randomly selected horse has enteroliths, given that it is fed more than 50% alfalfa, is:
A)0.23. 
B)0.348. 
C)0.08. 
D)0.2.

Quizplus · Accepted Answer

We need to find P(enteroliths|more than 50% alfalfa). Using the table, we see that out of the 103 horses fed more than 50% alfalfa, 36 have enteroliths. So, P(enteroliths|more than 50% alfalfa) = 36/103 = 0.348. Therefore, the best choice is B.

Veterinarians Suspect That Enteroliths (Calcifications in the Gut of Horses)