Question

Results from a marijuana drug test study showed 143 subjects with positive test results including 24 false positive results. There were 157 negative​ results, including 3 false negative results. What is the probability that a randomly selected subject did not use​ marijuana? Round to three decimal places as needed.

Answer 1

0.5933

Explanation:

Given that results from a marijuana drug test study showed 143 subjects with positive test results including 24 false positive results. There were 157 negative​ results, including 3 false negative results.

This can be tabulated as follows:

Used Marijuana Not used Marijuana Total

Results

Positive 143-24 =119 24 143

Negative 3 154 157

Total 122 178 300

We have to find that probability that a randomly selected subject did not use​ marijuana

Required prob = total people not used/total people

=
`(178)/(300) \\=0.5933`