Assignment Confusion Matrix

Task

Suppose we have a test for a disease. There are 800 test persons. 50 of them are sick. The test yields 100 positive results. 40 of the positively tested persons are positive in reality.

Create the confusion matrix and calculate the PPV (precision), NPV, sensitivity, and specificity

Solution

			Reality
		Positive	Negative	Sum
Test	Positive	40	60	100
	Negative	10	690	700
	Sum	50	750	800

PPV: 0.4

NPV: 0.986

Sensitivity: 0.8

Specificity: 0.92