Confidence-Calibration Practice for Estimation Questions
Give a 90% confidence interval, not a point answer — and learn to be honestly uncertain.
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Estimation questions — the 'Fermi' problems interviewers love — aren't really about the number; they're about whether you know how uncertain you are. The Calibration Trainer asks you for a 90% confidence interval rather than a point estimate, then scores you on honesty: if you say 90%, the truth should land inside your interval about 90% of the time.
Most people are badly overconfident, giving intervals far too narrow. Repeated calibrated practice fixes that — teaching you to widen intervals to match your real knowledge, which is exactly the self-aware reasoning trading interviews reward.
What it's modelled on
Estimation and confidence-interval interview questions
Rather than one named test, this trains a theme that recurs across trading interviews: estimation ('Fermi') questions and requests for a range instead of a point answer, which probe whether you know how uncertain you are. Well-calibrated reasoning is what interviewers are really checking for.
What it trains
- Estimation and Fermi-style reasoning
- Quantifying uncertainty with confidence intervals
- Calibration — matching stated confidence to real accuracy
How it's scored
Each round you give a 90% interval; you're scored on calibration (how often the truth lands inside) and tightness, not on hitting a single number. Free to play.
Related guides
Frequently asked questions
- What is a calibration question in an interview?
- Instead of a single estimate, you give a range you're (say) 90% confident contains the answer. It tests whether you understand your own uncertainty — a well-calibrated candidate's 90% intervals contain the truth about 90% of the time.
- How do I stop being overconfident on estimation questions?
- Practise giving explicit confidence intervals and check how often the truth actually falls inside them — most people need to widen their intervals substantially. The Calibration Trainer gives you that feedback loop directly.