Question

A new medical procedure has been shown to be effective in the early detection of a novel virus. A medical screening of the population is proposed.

Let D denote the event that one has the disease, then D^’ denotes the event that one doesn’t have the disease.

Let + denote the event that the test signals positive, and – denote the event that the test signals negative.

The probability that a new medical procedure correctly identifies someone with disease as positive (known as the sensitivity) is 0.98, that is P(+/D) = 0.98.

And the probability that the test correctly identifies someone without the disease as negative (known as the specificity) is 0.99, that is P(-/D^') = 0.99.

The incidence of the disease in the general population is 0.20, that is P(D) = 0.20.

One takes the test, and the result is positive. What is the probability that one has the disease? Round answer to 4 decimal places.

Answer 1