SOLUTION: Suppose that IQ scores are normally distributed with mean = 100 and Standard Dev. = 10. Find the 90th percentile of IQ scores. (nearest whole number) What is the x, y, p and q of

Algebra ->  Probability-and-statistics -> SOLUTION: Suppose that IQ scores are normally distributed with mean = 100 and Standard Dev. = 10. Find the 90th percentile of IQ scores. (nearest whole number) What is the x, y, p and q of      Log On


   



Question 383648: Suppose that IQ scores are normally distributed with mean = 100 and Standard Dev. = 10. Find the 90th percentile of IQ scores. (nearest whole number)
What is the x, y, p and q of this problem. The answer is 113, but how..

Found 2 solutions by stewbaby, Fombitz:
Answer by stewbaby(1) About Me  (Show Source):
Answer by Fombitz(32388) About Me  (Show Source):
You can put this solution on YOUR website!
Find the z-score so that P%28z%29=0.90.
Using EXCEL's NORMSINV for P%28z%29=0.90, z=1.281552.
z=%28x-mu%29%2Fsigma
%28x-100%29%2F10=1.28152
x-100=12.8152
x=112.8152
Rounding up, highlight%28x=113%29