Question

Assume that adults have IQ scores that are normally distributed with a mean of ?=100 and a standard deviation ?=20. Find the probability that a randomly selected adult has an IQ less than 140.

Answer 1

The probability that a randomly selected adult has an IQ less than 140 is 0.9772

Explanation:

Given:

Standard deviation: σ=20

Mean: μ=100

P(X<140)=?

Calculate:

normalcdf(lower,higher,μ,σ) = normalcdf(0,140,100,20) = 0.9772496509 ≈ 0.9772 ≈ 97.72%