SOLUTION: A principal claims that the students in his school are above average intelligence. A random sample of 30 IQ scores have a mean score of 112.5. Is there sufficient evidence to suppo

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Question 1188838: A principal claims that the students in his school are above average intelligence. A random sample of 30 IQ scores have a mean score of 112.5. Is there sufficient evidence to support principal’s claim? The mean population IQ is 100 with a standard deviation of 15
Answer by Edwin McCravy(20060)   (Show Source): You can put this solution on YOUR website!
On your TI-84,

Press ON
Press CLEAR
Press STAT
Use right arrow key to highlight TESTS
Press 1

Make screen read

         Z-Test
Inpt:Data Stats      <--(highlight Stats)
μ0:100
σ:15
x̄:112.5
n:30
μ:≠μ0  < μ0  > μ0  <-- Highlight > μ0
Calculate  Draw     <--highlight Calculate

Press ENTER

See this:
           Z-test
μ>100
z=4.564354646
p=2.507656533E-6
x̄:112.5
n:30

The p-value is extremely low p=2.507656533x10^-6 = 0.0000002507656533,
so the poem goes:

"When p is low, the null hypothesis must go."

So there is not sufficient evidence to support the principal's claim.

Edwin
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