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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Elliana 2 weeks 2021-11-16T03:04:23+00:00 1 Answer 0 views 0

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    2021-11-16T03:06:08+00:00

    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:

    z=\frac{X-\mu}{\sigma}

    We substitute to get:

    -0.675=\frac{X-98.8}{17.1}

    This implies that:

    17.1*-0.675=X-098.8

    -11.5425=X-098.8

    Solve for x to get:

    x=98.8-11.5425

    X=87.2575

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45:7+7-4:2-5:5*4+35:2 =? ( )