Question

Suppose that 2% of the students in a school have head lice and the test for head lice is accurate 75% of the time. What is the probability that a student in the school has head lice, given that the test came back positive? Round your answer to the nearest tenth of a percent.

Answer 1

If 2% of the student actually have head lice, but only 75% of that 2% will actually have a positive test result, then your probability of a result coming back positive would 75% of 2% (0.75 x 0.02). The answer is 0.02 chance.