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An IQ test produces scores that are normally distributed with mean value 100 and standard deviation 14.2. The top 1 percent of all scores are in what range?

I'm not entirely sure what the question is even asking.

I understand that the bottom is equal to 1 - 0.01 = 0.99 but is this information even necessary?

Thank You

agelakute
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    50 percent of scores are at least 100. Way less than 50 percent are at least 110, and even fewer are at least 120. You're being asked how far above 100 you have to go to get 99% of tests below that. –  Apr 17 '18 at 17:38
  • Suppose $X$ is the IQ score of an individual chosen at random. You are asked to determine $a$ such that $P(X>a) = 0.01$. – awkward Apr 17 '18 at 20:32

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Looking up z-table for Pr(0.99) I get 2.33

using $$ Z= \frac{X-x}{\sigma} $$ I get x=14.2*2.33+100 =133.086

Kirsten
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