Suppose that researchers developed a test to detect a disease in the general population. However, the test was not perfect. To determine the accuracy of the test, a study was done on 2000 subjects, 1000 of whom were known to have the disease and 1000 of whom were known to be disease-free. Some results are shown below in the following table:

Group	positive	negative	total
Subject with disease	750		1000
subject without disease			1000
Total		1100

Fill the blank cells in the above table.

What is the probability that if a disease-free person is randomly selected, they

will test positive?

What is the probability that a person tests negative or is a subject known to be

disease-free?

Find the diagnostic sensitivity, diagnostic specificity, PPV and NPV for this test.

Describe what each of these values mean as probabilities.