Tests for diseases can sometimes be wrong there are two type

Tests for diseases can sometimes be wrong, there are two types of errors that can occur; indicating a disease is present when it isn\'t, or failing to indicate a disease is present when it is. The table below gives some results for one such test: What is the probability that the disease is present given that the test is positive? What is the probability that the disease is not present given that the test is negative? Without making any changes to the test, what can be done to improve the accuracy of the testing procedure to determine that a patient either has or doesn\'t have the disease?

Solution

sol) Probability that the disease is present given that the test is positive

Total patients=135

Number of patients disease is present given that the test is positive=25

Probability that the disease is present given that the test is positive=25/135 =0.185

b) Probability that the disease is not present given that the test is negative

Total patients=135

Number of patients disease is present given that the test is positive=78

Probability that the disease is present given that the test is positive=78/135 =0.577