Given a Binomial Distribution with N Trials and Probability P

Short Answer

Given a binomial distribution with n trials and probability p of a success on any trial, a conventional rule of thumb is that the normal distribution will provide an adequate approximation of the binomial distribution if: $\begin{array}{|l|l|}\hline A&n p \geq 5 \text { and } n(1-p) \geq 5 \\\hline B&n p \leq 5 \text { and } n(1-p) \leq 5\\\hline C&n p \geq 5 \text { and } n(1-p) \leq 5\\\hline D&n p \leq 5 \text { and } n(1-p) \geq 5\\\hline \end{array}$