Question

A lie detector test detects a person telling a lie 50% of the time, but 11% of the time it detects a lie when a person is telling the truth. Consider the null hypothesis, "a person is telling the truth during a lie detector test." What is the probability of a Type I error?

Write your answer as a decimal value.

Answer 1

Ho : Person telling the truth in lie detector test

H1 : Person telling the lie in lie detetcor test

we have given that

probability of detecting lie when person telling lie = 0.5 ...........(1)

probability of detecting lie when person telling truth = 0.11........(2)

Type I error = Accepting H1 when Ho is true

in this case

Type I error = Detector detect that person telling lie when person actually telling truth

from (2)

Probability of detector detect that person telling lie when person is actually telling truth is  0.11

Probability of type I error is 0.11