Question 933271
Using a TI-84, I get


invNorm(0.90) = 1.28155


So z = 1.28155, and we'll use this to find the raw score x


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z = (x-mu)/sigma


1.28155 = (x-1200)/100


1.28155*100 = x-1200


128.155 = x-1200


128.155+1200 = x


1,328.155 = x


x = 1,328.155


Round up to the nearest whole number to ensure you clear the hurdle. So you need to score a 1329 or higher to be in the 90th percentile or higher.


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