Home · Unit 3 · Topic 5 · General discrete random variables

General discrete random variables

Determine and use the variance of a discrete random variable as a measure of spread, 𝑉𝑎𝑟(𝑋) = ∑ 𝑝𝑖 (𝑥𝑖 − 𝜇)2 where 𝑝𝑖 is the probability of outcome 𝑥𝑖 occurring, 𝜇 is the mean.

mm-u3-t5-s1-d6

Interactive

Variance as spread of a discrete RV

manipulative

Variance is the mass-weighted average of squared distance from μ — spread the sticks and Var grows; pile them on μ and it collapses.

Open fullscreen →

Want a different take?

Already have one and want another angle on this point? Describe what students should notice. Requests are read and acted on.