1a. Approximately 2 percent of women ages 40-50 have breast cancer. A woman has a 80 percent chance of a positive test from a mammogram given she has breast cancer (a true positive result). A woman has a 6 percent chance of a positive test from a mammogram given she does not have breast cancer (a false positive result).

Complete the table below, then answer the questions below the table. Give all answers as decimals to 4 decimal places.

1b.What is the probability a woman has breast cancer given that she just had a positive test?

Give answer as decimals to 4 decimal places.

	Positive Test Result	Negative Test Result	Total
Has breast cancer
Does not have breast cancer
Total

1c. A certain virus affects 0.5% of the population. A test used to detect the virus in a person is positive 87% of the time if the person has the virus (true positive) and 12% of the time if the person does not have the virus (false positive). Fill out the remainder of the following table and use it to answer the two questions below based on a total sample of 100,000 people.

	Virus	No Virus	Total
Positive Test
Negative Test
Total

1d. Find the probability that a person has the virus given that they have tested positive. Round your answer to the nearest hundredth of a percent and do not include a percent sign. %

1c Find the probability that a person does not have the virus given that they test negative. Round your answer to the nearest hundredth of a percent and do not include a percent sign. %