IQ test scores are standardized to produce a normal distribution with a mean of = 100

Question:

IQ test scores are standardized to produce a normal distribution with a mean of μ = 100 and a standard deviation of σ = 15. Find the proportion of the population in each of the following IQ categories.

a. Genius or near genius: IQ greater than 140

b. Very superior intelligence: IQ between 120 and 140

c. Average or normal intelligence: IQ between 90 and 109?

Distribution
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