Question

Scores of an IQ test have a bell shaped distribution with a mean of 100 and a standard deviation of 19. Use the empirical rule to determine the following.

a.) What % of people has an IQ score between 81 and 119?

Answer 1

Z score for 81 is (81-100)/19=-1
Z score for 119 is (119-100)/19=+1
Use normal distribution table to find the difference in probability between -1 and +1. It should be around 68%.

Answer 2

32%