Screening Test Statistics

Probability of condition given test result 50.00
Positive Predictive Value 50.00
Negative Predictive Value 50.00
Negative Test Positive Test

Sensitivity is the probability of testing positive if you are sick. The probability of a false-negative is 100% minus the sensitivity.

Specificity is the probability of testing negative if you are healthy. The probability of a false-positive is 100% minus the specificity.

The probabaility of you being sick given a test result depends on how prevelant the condition is overall (the base rate). This is confusing at first, but it helps to think in terms of extremes: