Finding the Sample Size (VCE SSCE Mathematical Methods): Flashcards

Working backwards from desired probability

Must be whole number; can't have fractional trials

$Pr(X \geq 1) = 1 - Pr(X = 0)$

Reverses the inequality sign

Fixed $n$, two outcomes, constant $p$, independent trials

$(1-p)^n$ or $q^n$ where $q = 1-p$

When inequality can't be solved algebraically

$Pr(X = 0) < 0.05$

Larger sample size

Number of trials or sample size