This is what the Cambridge textbook says (Key Ideas) (page 800):
- A binomial distribution can be approximated by the normal distribution with the same mean and standard deviation.
- Thus the binomial distribution B (n, p) or Bin (n, p) can be approximated by the normal distribution N (np, npq) , where q = 1 − p.
- N (μ, σ^2) means the normal distribution with mean μ and variance σ2.
- When approximating, we treat the discrete binomial variable X as if it were a continuous normal variable.
- For small values of n, apply the continuity correction. This means integrating between half- intervals, corresponding to the boundaries of the cumulative frequency histogram. For example, to approximate P (X = 8, 9, 10, 11 or 12) , we treat X as a continuous normal variable and find P(7.5 ≤ X ≤ 12.5).
I'm a bit confused as to what a "small value of n" can be defined as. Like what would be the cutoff point?