Tool:       For large n and p ≈ 1/2, the binomial distribution approximates a normal (or gaussian) distribution with mean μ = np and standard deviation .

Tool:       For large n and p ≈ 1/2, the binomial distribution summed from m = 0 to m = r approximates the cumulative distribution of a normal (or gaussian) distribution with mean μ = np and standard deviation . In other words, the following equation applies:

where and