Mathematical Methods · discrete RVs · manipulative

Variance is spread around μ

Each stick sits some distance from the gold fulcrum μ. Variance is the probability-weighted average of those squared distances.

P(X = x) fulcrum μ (x − μ)²
Var(X)
—
Σp = 1 Var = —

Preset

Sticks stay a valid pmf (auto-renormalise). Drag tops or scrub. Amber squares grow with |x − μ|.

Probabilities pᵢ

Working

μ = —