SOLUTION: Assume that adults have IQ scores that are normally distributed with a mean of 95.5 and a standard deviation 23. Find the first quartile Upper Q 1​, which is the IQ score separat

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Question 1160358: Assume that adults have IQ scores that are normally distributed with a mean of 95.5 and a standard deviation 23. Find the first quartile Upper Q 1​, which is the IQ score separating the bottom​ 25% from the top​ 75%.
Answer by Boreal(15235) About Me  (Show Source):
You can put this solution on YOUR website!
on calculator do VARS 3 invnorm and input .75, 95.5, 23 and get 111.01

z for the upper quartile, or 75th percentile, is 0.6745
z=(x-mean)/sd
0.6745=(x-95.5)/23
15.51=x-95.5
x=111.01