Question

Suppose that IQ scores have a bell-shaped distribution with a mean of 9595 and a standard deviation of 1818. Using the empirical rule, what percentage of IQ scores are no more than 149149? Please do not round your answer.

Answer 1

Solution :

Given that ,

mean = = 95

standard deviation = = 18

Pr(41X131) = 0.997

The normal distribution is symmetric, then we also conclude that half of that probability (0.003/2 = 0.0015) goes to each of the two tails. This means that

P(X41) = 0.0015

P(X149) = 1−0.0015 = 0.9985