Question

Assume that adults have IQ scores that are normally distributed with a mean of 100.5 and a standard deviation 20.5. Find the first quartile Upper Q 1​, which is the IQ score separating the bottom​ 25% from the top​ 75%. (Hint: Draw a​ graph.) The first quartile is nothing. ​(Type an integer or decimal rounded to one decimal place as​ needed.)

Answer 1

From the Question, Mean = 100.5 and Std. Deviation = 20.5

and we have to find Value

Refering to the Standard Z-Table,

Therefore, Subtituting the Values in the Above Formula:

Value = 86.6625

Therefore, the Value Separating bottom 25% from Top 25% is 86.6625

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