FIND PROBABILITY STATS

Question

Assume that adults have IQ scores that are normally distributed with a mean of μ=105 and a standard deviation σ=15. Find the probability that a randomly selected adult has an IQ less than 120.

Answer 1

Obtain a z-score table: http://users.stat.ufl.edu/~athienit/Tables/Ztable.pdf

z = (120 - 105) / 15

z = 15 / 15

z = 1

84.13% have scores lower than 120