Continuity correction is a statistical technique used to approximate a discrete probability distribution by applying a continuous probability distribution.
It is commonly applied when using the normal distribution to approximate the binomial distribution.
The following calculator allows you to compute the approximate probabilities. You need to specify the parameters for the binomial distribution:
Exact Binomial Probabilities
P(X = 43) = 0.06673
P(X < 43) = 0.69674
P(X ≤ 43) = 0.76347
P(X > 43) = 0.23653
P(X≥ 43) = 0.30326
Approximated Probabilities
P(42.5 < X < 43.5): 0.06744
P(X < 43.5): 0.76252
P(X < 42.5): 0.69508
P(X > 42.5): 0.30492
P(X > 43.5): 0.23748
The idea behind continuity correction is to adjust the boundaries of the discrete distribution by adding or subtracting a correction factor of 0.5 to better align with the boundaries of the continuous distribution.
This adjustment helps to improve the accuracy of approximating probabilities and making calculations involving the discrete distribution with a continuous distribution.
Note that the correction factor is always 0.5 and can’t be zero.