Question

Suppose that a test for determining whether a person has been infected with COVID-19 has a 20% rate of false positives (i.e. in 20% of applications, the test falsely indicates that a person has been infected with COVID-19 when they actually have not). Now, consider the likelihood that when 100 healthy people are tested, the test falsely indicates that between 10 and 30 of them are infected.

c. Before you use the normal approximation to calculate P(10 ≤ x≤ 30), you will need to make continuity corrections to x1=10 and x2=30. Report the continuity-corrected values for x1 and x2 that you should you use instead.

d. Calculate the z-scores using the continuity-corrected values of x1 and x2 from part d.

e. Look up the z-scores from part e and report the probabilities that you found.

Answer 1