Tuesday

July 29, 2014

July 29, 2014

Posted by **Anonymous** on Wednesday, February 11, 2009 at 2:47pm.

a) What is the probability that both test yield the same result?

B) If both tests are positive, what is the probability that the selected individual is a carrier?

i have no idea on where to start.

- statistics -
**economyst**, Wednesday, February 11, 2009 at 4:20pmExcel spreadsheets are very helpful for these kinds of problems.

Start by building a probability tree, calculate all possible values. There are 2 kinds of people (with and without), and each test has two answers (yes, no). So, there should be 8 possible outcomes.

The probability of seeing a person with the disease and both test positive is: .01*.9*.9 = .0081

of seeing a person with the disease and the first test is positive and the second negative = .01*.9*.1 = .0009

Repeat for the other 6 possibilities. If you did the calculations right, the sum of the 8 values should be 1.0.

Then you will have all the information you need.

**Related Questions**

pstat.................HELP........................ - A diagnostic test for a ...

math - This is a statistics problem. A laboratory test for the detection of a ...

Statistics - A group of doctors is trying to see if a vaccine causes a certain ...

Math - Can someone please help me? certain medical diagnostic test is used to ...

Probability - Can someone please help me? certain medical diagnostic test is ...

Probability - Can someone please help me? certain medical diagnostic test is ...

STATISTICS - A particular diagnostic test for disease X has a sensitivity of 90...

STATISTICS - A particular diagnostic test for disease X has a sensitivity of 90...

statistics - A test designed to check for sickle-cell anemia has an 85% chance ...

Probability - Suppose that 3% of the population ha a certain disease. We have a ...