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Can i get some help with these porblems? Can it be show in excel with the formul

ID: 3174979 • Letter: C

Question

Can i get some help with these porblems? Can it be show in excel with the formulas showing.

A certain set of diseases will make it so that a person cannot donate blood. These diseases affect 2% of the population. The donor s are tested and if a donor has one of these diseases, the test will detect it 99% of the time. Suppose the test is given to a randomly selected group of donors and 3.5% test positive for one of these diseases. What is the probability that a donor actually does have one of these diseases, given that the test detected a disease?

Explanation / Answer

Probability that a person has any of the diseases, P(D) = 0.02
Probability that the test detects the diseases, P(T|D) = 0.99
For a given group of donors, probability of positive test P(P) = 0.035

Hence probability that a donor actually has a disease provided test is positive,
P(D|T) = P(T|D)*P(D) / P(P)
P(D|T) = 0.99*0.02/0.035 = 0.5657

Required probability = 0.5657