Choosing Distributions (A Level only) (Edexcel A-Level Mathematics): Flashcards

They model real-world situations and predict outcomes.

It models successes in a fixed number of independent trials.

When trials are fixed, independent, and have two outcomes.

$P(X = k) = \binom{n}{k} p^k (1-p)^{n-k}$.

It's continuous, symmetric, and bell-shaped around the mean.

68% within $1\sigma$, 95% within $2\sigma$, and 99.7% within $3\sigma$.

Continuous data in a symmetric, bell-shaped distribution.

$Z = (X - μ) / σ$.

Use $P(Z < z)$ values from the $z$-table for standard normal.

Identify the situation and fitting distribution.