Please help...Thank you

Question

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

u equals 105μ=

and a standard deviation

sigma equals 20σ=.



Find the probability that a randomly selected adult has an IQ between

93

and

117.

Answer 1

Prob( 93 < x < 117) =

Prob( (93-105)/20 < z < (117-105)/20 ) =

Prob( -12/20 < z < 12/20) =

Prob( -0.8 < z < 0.8) =

Prob( z < 0.8) - Prob(z<-0.8) = 0.57628