Level 2: Conditional probability
Bayes' theorem, base rates, and updating on evidence — where intuition fails most reliably and interviewers probe hardest.
36 problems
First 5 free · rest Premium
- 1→
The Monty Hall Problem
●●●○○Medium~5 min
- 2→
The Two-Children Problem
●●●○○Medium~5 min
- 3→
False Positives and Base Rates
●●●○○Medium~5 min
- 4→
Which Coin Did I Flip?
●●○○○Easy~4 min
- 5→
The Blue-Cab Problem
●●●○○Medium~5 min
- 6Premium
The Three Prisoners
●●●●○Hard~7 min
- 7Premium
Bertrand's Box Paradox
●●●○○Medium~5 min
- 8Premium
The Prosecutor's Fallacy
●●●○○Medium~6 min
- 9Premium
Simpson's Paradox
●●●●○Hard~7 min
- 10Premium
The Tuesday Boy
●●●●○Hard~7 min
- 11Premium
Monty Hall with 100 Doors
●●○○○Easy~4 min
- 12Premium
Aces: 'At Least One' vs 'The Ace of Spades'
●●●●○Hard~7 min
- 13Premium
Laplace's Rule of Succession
●●●●○Hard~7 min
- 14Premium
Monty Hall with a Clueless Host
●●●○○Medium~5 min
- 15Premium
Which Urn Did the Ball Come From?
●●●○○Medium~5 min
- 16Premium
Two Positive Tests
●●●○○Medium~6 min
- 17Premium
The Pólya Urn
●●●●○Hard~7 min
- 18Premium
The Conjunction Fallacy
●●○○○Easy~4 min
- 19Premium
The Two-Envelope Paradox
●●●●○Hard~7 min
- 20Premium
Monty Hall with a Biased Host
●●●●○Hard~7 min
- 21Premium
Conditioning on a Region
●●●○○Medium~5 min
- 22Premium
Carrier Probability
●●●○○Medium~5 min
- 23Premium
The Coin Has No Memory
●●○○○Easy~4 min
- 24Premium
The Lost Boarding Pass
●●●●○Hard~8 min
- 25Premium
Which Flip Was the Head?
●●○○○Easy~3 min
- 26Premium
Transfer Then Draw
●●●●○Hard~6 min
- 27Premium
Fair, Two-Headed, or Two-Tailed?
●●●○○Medium~5 min
- 28Premium
Which Machine Made the Defect?
●●●○○Medium~5 min
- 29Premium
How Reassuring Is a Negative?
●●●○○Medium~5 min
- 30Premium
The Multiple-Testing Trap
●●●○○Medium~6 min
- 31Premium
I Met One of His Children
●●●○○Medium~6 min
- 32Premium
Bertrand's Chord Paradox
●●●●○Hard~7 min
- 33Premium
Expectation Given a Threshold
●●●○○Medium~5 min
- 34Premium
Splitting a Poisson Total
●●●●○Hard~6 min
- 35Premium
Fair or Biased After a Sequence?
●●●○○Medium~5 min
- 36Premium
Cold Hit vs Probable Cause
●●●●○Hard~7 min