Assume that adults have IQ scores that are normally distribu

Assume that adults have IQ scores that are normally distributed with a mean of mu = 105 and a standard deviation sigma = 15. Find the probability that a randomly selected adult has an IQ less than 129. The probability that a randomly selected adult has an IQ less than 129 is

Solution

Normal Distribution
Mean ( u ) =105
Standard Deviation ( sd )=15
Normal Distribution = Z= X- u / sd ~ N(0,1)                  
P(X < 129) = (129-105)/15
= 24/15= 1.6
= P ( Z <1.6) From Standard Normal Table
= 0.9452