SOLUTION: Assume that adults have IQ scored that are normally distributed with a mean of 100 and a standard deviation of 15. Find the probabilty that a randomly selveted adult has an IQ betw

Algebra ->  Probability-and-statistics -> SOLUTION: Assume that adults have IQ scored that are normally distributed with a mean of 100 and a standard deviation of 15. Find the probabilty that a randomly selveted adult has an IQ betw      Log On


   

Question 314863: Assume that adults have IQ scored that are normally distributed with a mean of 100 and a standard deviation of 15. Find the probabilty that a randomly selveted adult has an IQ between 81 and 119? I can't find thee formula on how to find the answer.
Answer by Fombitz(32388) About Me  (Show Source):
You can put this solution on YOUR website!
Find the z scores for both values.
z=%28x-mu%29%2Fsigma
.
.
.
z1=%2881-100%29%2F15=-1.267
z2=%28119-100%29%2F15=1.267
Find the normal probability value for both of these z scores.
I used EXCEL's NORMDIST function(CUMULATIVE=TRUE).
P1=0.1026237
P2=0.897363
The probability for the values to lie between 81 and 119 is the difference in probability values.
P=0.897363-0.1026237
P=highlight_green%280.795%29