Learnova
Library
Data & Probabilitybeginner

Chance & Uncertainty

Probability built from counting, not formulas. Learn when to multiply, when to take the complement, and why a 99%-accurate test can still be wrong most of the time.

3 lessons46 min totalup to 183 XP

Lessons

  1. 1What Probability Actually Meansnext upOut of how many? Every probability question reduces to that one question.easy14 min+55 XP
  2. 2Combining ChancesAnd, or, and 'at least one'. Three rules, one of which quietly does most of the work.medium16 min+62 XP
  3. 3The Base Rate TrapHow a 99%-accurate test can be wrong four times out of five — and how to see it coming.hard16 min+66 XP