A required condition for using the normal approximation to the binomial in testing the difference between two population proportions is that n₁p₁ ≥ 30 and n₂p₂ ≥ 30.

Question

Quizplus · Accepted Answer

The correct condition for using the normal approximation to the binomial in testing the difference between two population proportions is that both $n_1p_1(1-p_1) \geq 10$ and $n_2p_2(1-p_2) \geq 10$, where $n_1$ and $n_2$ are the sample sizes, and $p_1$ and $p_2$ are the sample proportions for the two groups being compared. The threshold value is generally considered to be 10, not 30.

A Required Condition for Using the Normal Approximation to the Binomial