Advanced
Expected value, variance, and sample size
The arithmetic of long-run outcomes, and why short samples are close to uninformative.
AI summary
No summary is published for this page. When summaries are enabled they will restate only what this page already publishes — the lesson body on this page, reduced to key takeaways. — and each one will carry the model name and the time it was generated.
Status: reserved · no generated text on this page
How this lesson runs
- 01
The calculation
- 02
Sample size
- 03
Model humility
Want this applied to a specific price? The Sports.co Analyst walks through the arithmetic. It explains method only — never picks.
Video walkthrough: Expected value, variance, and sample size
No verified video is linked here yet. This slot fills only with official or first-party footage we can attribute on screen.
The calculation
Expected value is the probability-weighted outcome minus cost. If your probability estimate is 55% against a price implying 52%, the difference is the estimated edge — before fees, and only as good as the estimate itself.
Sample size
With a small theoretical edge, a large number of observations is needed before results can be distinguished from noise. Short-run results are dominated by variance.
Model humility
Estimated probabilities carry error. Treating a point estimate as certain is the most common analytical failure in this area — which is also why this site publishes no confidence scores it cannot substantiate.
Sources
No source is connected to this section yet. Nothing here should be read as a current factual claim.
Method explained in our own words. This lesson asserts no market price, result, or statistic.
Continue
- LearnEducational long-form, levelled from foundation to advanced.
- Odds formats: American, decimal, and fractionalThree notations for the same underlying quantity. Learn to convert between them and to see the i
- Implied probability and the marginEvery posted price is a probability with a margin attached. Removing that margin is the first an
- Line movement and market efficiencyHow prices update, which moves tend to carry information, and why the closing number is a widely
- Odds guidesMethod explainer with worked arithmetic and a HowTo schema block.
- CalculatorsTool page: arithmetic on user input, so it needs no external feed.