Question

A test subject is randomly selected for a pregnancy test. What is the probability of getting a subject who is not pregnant, given that the test result is positive? Find the probability using the data table.
See attachment below for table and answer choices :-)

Answer 1

First we need to choose from "Posivite Test" column:
$\frac{12}{12+78} = \frac{12}{90} = 0,1333(3)$ 

Answer 2

The correct answer is:

0.13

Explanation:

Using the two-way table, we focus on the column labeled "Positive Test." There are 78+12 = 90 people who had a positive test. Out of these, 12 were not pregnant. This is a probability of 12/90 = 0.133333 = 0.13.