X is a normally distributed random variable with mean 39 and standard deviation 17. What is the probability that X is between 22 and 73?

Answer 1

For X = 22, z = (22 - 39) / 17 = -1

For X = 73, z = (73 - 39) / 17 = 2

So, P(22 < X < 73) = P(-1 < z < 2) = 0.341 + 0.341 + 0.136 = 0.682 + 0.136 = 0.818