Standard normal distribution question!. assume that adults have IQ scores that are normally distributed with a mean of 100 and a standard deviation 20. Find P15, which is the IQ score separating the bottom 15% from the top 85%

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Mathematics

Miguel Haney

15 February, 21:30

Standard normal distribution question!. assume that adults have IQ scores that are normally distributed with a mean of 100 and a standard deviation 20. Find P15, which is the IQ score separating the bottom 15% from the top 85%

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Zaire Wise · Answer 1

The 15th percentile (area below which 15 % of cases lie in a standard normal distribution is, from tables - 1.04

z = (x-mean) / sd

-1.04 = (x-100) / 15

x=100+15 (-1.04) = 84.4