## Assume that adults have IQ scores that are normally distributed with a mean of 98.8 and a standard deviation 17.1. Find the first quartile

Question

Assume that adults have IQ scores that are normally distributed with a mean of 98.8 and a standard deviation 17.1. Find the first quartile Q1, which is the IQ score separating the bottom 25% from the top 75%. (Hint: Draw a graph.)

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2021-11-16T03:04:23+00:00
2021-11-16T03:04:23+00:00 1 Answer
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## Answers ( )

Answer:The IQ score separating the bottom 25% from the top 75%. is 87.3

Step-by-step explanation:Given that adults have IQ scores that are normally distributed with a mean of 98.8 and a standard deviation 17.1.

To find the first quartile, we calculate X such that P(X<z)=0.25.

From the normal distribution table the The z-value that corresponds to an area of 0.25 is z=-0.675

We use the formula:

We substitute to get:

This implies that:

Solve for x to get:

X=87.2575