Poisson & Binomial Distributions (Edexcel A-Level Further Mathematics): Flashcards

$n$ large and $p$ small

$\lambda = np$

$np \leq 10$

$\frac{\lambda^x e^{-\lambda}}{x!}$

$\binom{n}{x} p^x (1-p)^{n-x}$

Simplifies calculations for large $n$, small $p$

Rare events over time or space

Mean and variance

When $n$ small or $p$ large

Forgetting factorial $x!$ in denominator