📈 Lesson 2: What "62% Confidence" Looks Like

Confidence isn't a single number — it's a distribution

When the analysis says "62% confidence Braves win," that's not certainty — it's the CENTER of a probability distribution. The real win probability could be 55%, 62%, or 70%. We have uncertainty about the uncertainty.

The right tool for this in math is the Beta distribution. It's a curve that shows how likely each possible "true win probability" is.

📊 Interactive: Beta Distribution Explorer

Adjust α (alpha) and β (beta) to see how the distribution shape changes:

Mean (expected win rate): --
95% confidence interval: --
Mode (most likely): --

📖 What This Teaches You

Small samples = wide distributions

If you've only seen 8 wins and 5 losses, the "true win rate" could be anywhere from 35% to 80%. Your point estimate (61.5%) is meaningless.

Large samples = sharp distributions

After 120 wins and 75 losses, the distribution tightens around 61.5%. NOW you can trust the number.

Why we use Beta, not Gaussian

Win/loss is binary (0 to 1). Beta naturally lives in this range. Gaussian (the bell curve) goes from -∞ to +∞ — wrong shape for probabilities.

For our bets: We currently have N=1 bet (Pistons G4 loss). Our "win rate distribution" is Beta(0+1, 1+1) = Beta(1, 2). It says: "Could be anywhere from 0% to 75%, we have no idea." This is WHY we don't claim accuracy yet. Need 20-30 bets minimum.

📊 Gaussian: For Continuous Outcomes

For things like point spreads (margin of victory), use the Normal/Gaussian distribution. NBA point spreads have a Gaussian-ish shape — most games land near the spread, with diminishing tails.

Spread = 4.5 0 +4.5 +10 -10 +20 Margin of victory →

If Pistons are favored by 4.5, the average expected margin is 4.5 — with a standard deviation of maybe 10-12 points. The probability they cover (margin > 4.5) is roughly 50%.