False Positive Calculator

iPhone / Education

This False Positive QC Calculator is a precision quality-control tool for laboratories, researchers, and clinicians who monitor test performance over large batches.

This app answers the following:

If the true false-positive rate is p, how likely is it to observe k or more false positives in n tests?

What the app does

The calculator models false-positive counts using a binomial process and computes the probability of observing results that are as extreme or more extreme than what you saw. This probability is commonly used as a QC “alarm” or plausibility check.

A quality-control calculator that shows how likely it is to observe many false positives in a test run, given a known false-positive rate.

Teaching statistical quality control concepts

How it works

Assumes independent tests with a constant per-test false-positive probability

Uses the binomial distribution: K ~ Binomial(n, p)

Computes P(K ≥ k), the probability of observing k or more false positives

Calculator flow

The app guides you step-by-step:

Enter the total number of tests (n)

Enter the known false-positive rate (p, as a percent)

Enter the observed number of false positives (k)

View the calculated probability and expected false-positive count

Important note

This app is a quality-control calculator, not a diagnostic tool.
It does not estimate disease probability, predictive value, or individual test validity.

Credit

The statistical formulation is credited to:

Dr. Man S. Oh
Professor of Medicine
SUNY Downstate Medical Center
Brooklyn, New York