As a result, we can approximate the binomial distribution B(n, p) using the normal distribution
N(μ, o) so long as we meet two conditions:
1. The expected number of successes is at least 10, i.e. np > 10
2. The expected number of failures is at least 10, i.e. n(1 − p) ≥ 10
If these two conditions are met, then we can transform a difficult difficult probability
calculation, such as P(X < k) or P(X ≤ k) into a simpler probability problem using the
standard normal distribution (the Z-table!).
Give the formula for computing the z-score of k:
P(X < k) = P (Z <_____)
