# How to determine the accuracy of three combined tests

#### mjolnir91

##### New Member
Hypothetically, I have three tests that can determine if someone has cancer or doesn't have cancer. A True positive would indicate that the person doesn't have cancer. Below is a description of each test.

Test 1: TP=.7 , FN = .3 , FP= .1 , TN = .9 , Accuracy = 80%
Test 2: TP=.8 , FN = .2 , FP= .2 , TN = .8 , Accuracy = 80%
Test 3: TP=.6 , FN = .4 , FP= .47 , TN = .53 , Accuracy = 56.5%

(TP = true positive, FN = false negative, FP = false positive, TN = true negative)

What calculation can be done to determine how certain one could be that someone has cancer given that all three tests indicate the patient has cancer?

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