Suppose that 24% of all sales in a grocery store are for amounts greater than $100

In a random sample of 50 invoices, what is the probability that more than ten of the invoices are for over $100? Use the normal approximation for the binomial distribution.

P = 0.24, n = 50, ? =E(X) = nP = 12, ?2 = Var(X) = nP(1 - P) = 9.12, ? = 3.02
Without continuity correction P(X > 10 ) = P(Z > -0.66 ) = 0.7454.