Exercise 10 page 339

Find the probability that among 10,000 random digits 3 appears not more than 931 times.

mu <- 10000 * (1/10)
sd <- sqrt(10000 * 0.1 * 0.9)
x_931 <- (931 - 1000) / sd

\[P(Sn_{10,000} \leq 931) \\ P(^*Sn_{10,000} \leq \frac{931 - 1000} {30})\\ P(^*Sn_{10,000} \leq -2.3)\]

If we look at a Z-score table we find that the probability is 0.0107