Approximating Binomial Probabilities Using the Normal Distribution

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Approximating Binomial Probabilities Using the
Normal Distribution
Let X be the number of successes from n
independent Bernoulli trials, each with
probability of success ?. The number of
successes, X, is a Binomial random variable and
if np(1 - p) gt 9 a good approximation is Or if
5 lt np(1 - p) lt 9 we can use the continuity
correction factor to obtain where Z is a
standard normal variable.