A continuity correction factor is used when you use a continuous
function to approximate a discrete one. For example, when you want to
approximate a binomial with a normal distribution. According to the Central Limit Theorem, the sample
mean of a
distribution becomes approximately normal if the sample size is
large enough. The binomial distribution can be approximated with a normal distribution too, as
long as n*p and n*q are both at least 5. So the answer is large
