SOLUTION: Looking at IQ-Tests, let us assume a standard IQ design that is �=100 and σ=15 to answer the question. From what score to what other score accounts for the middle 50 percent?

Question 873841: Looking at IQ-Tests, let us assume a standard IQ design that is �=100 and σ=15 to answer the question.
From what score to what other score accounts for the middle 50 percent? What actual score corresponds to the top 80th percentile?
I believe this has something to do with converting to a z-score, but I am not sure where to start.
Answer by reviewermath(1029) (Show Source): You can put this solution on YOUR website!
Looking at IQ-Tests, let us assume a standard IQ design that is �=100 and σ=15 to answer the question.
From what score to what other score accounts for the middle 50 percent?
For the lower score, enter the following formula in Excel:
=100+15*NORMSINV(.25)
The result is 89.8827
For the upper score, enter the following formula in Excel:
=100-15*NORMSINV(.25)
The result is 110.1173
Therefore, the middle score is from to

What actual score corresponds to the top 80th percentile?
To get the 80th percentile, enter the following formula in Excel:
=15*NORMSINV(0.8)+100
The result is

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SOLUTION: Looking at IQ-Tests, let us assume a standard IQ design that is �=100 and &#963;=15 to answer the question. From what score to what other score accounts for the middle 50 percent?

SOLUTION: Looking at IQ-Tests, let us assume a standard IQ design that is �=100 and σ=15 to answer the question. From what score to what other score accounts for the middle 50 percent?