Question

Assume that adults have IQ scores that are normally distributed with a mean of

mu equals 100 μ=100 and a standard deviation sigma equals 15 σ=15. Find the probability that a randomly selected adult has an IQ less than 121

The probability that a randomly selected adult has an IQ less than121 is ________.

​(Type an integer or decimal rounded to four decimal places as​ needed.)

Answer 1

Solution :

Given that mean μ = 100 , standard deviation σ = 15

=> P(x < 121) = P((x - μ)/σ < (121 - 100)/15)

= P(Z < 1.4)

= 0.9192

=> The probability that a randomly selected adult has an IQ less than 121 is 0.9192