Question

Use a normal approximation to find the probability of the indicated number of voters. In this case assume that 150 eligible voters aged 18-24 are randomly selected. Suppose a previous study showed that among eligible voters aged 18-24, 22% of them voted.
The probability that fewer than 39 of 150 eligible voters voted is

Answer 1

The number of people who voted follows a binomial distribution with probability of having voted $p=0.22$ and $n=150$ subjects, which means the approximating normal distribution should have mean $np=33$ and standard deviation $\sqrt{np(1-p)}\approx5.07$.

With the continuity correction, you have

$\mathbb P(X$