The IQ scores are normally distributed with a mean of 100 an

The IQ scores are normally distributed with a mean of 100 and a standard deviation of 15.

Find the 90th percentile of the IQ distribution.

Solution

Iq Scores are N: (100, 15)

IF x is the 90th percentile then (x-100)/15 is the 90th percentile for Z, std normal variatae

From the table we get z value as

z = 1.28

x = 100+15(1.28) = 119.20

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()th percentile of IQ distribution = 119.2