All labs
Maths ~4 minBayes’ theorem, base rates, conditional probability

A positive test isn’t a 99% chance

An accurate test says positive. How worried should you be?

Maths · ~4 min · live model
Loading the lab…

Make a prediction, then push the model. What you discover is recorded here.

The idea behind this lab (open after you’ve tried it)

When a condition is rare, false positives from the large healthy group can outnumber the true positives.

Go deeper than one lab.

A full quest builds the idea step by step, with checks and a new case to apply it to.

Start this quest

More labs