Mathematical Methods · discrete RVs · manipulative

Expected value as balance point

The gold fulcrum under the sticks is μ = E(X). Push mass around — the fulcrum is the expected value.

P(X = x) fulcrum = μ = E(X)
Σp = 1 μ = —

Preset

Sticks stay a valid pmf (auto-renormalise). Drag tops or scrub.

Probabilities pᵢ

Working

Fulcrum = E(X) = μ
—