SOLUTION: a set of test scores is normally distributed with a mean of 74 and a standard deviation of 8. Between what two scores does the middle 95% of the data fall?

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Question 194668This question is from textbook Saxon Algebra 2
: a set of test scores is normally distributed with a mean of 74 and a standard deviation of 8. Between what two scores does the middle 95% of the data fall? This question is from textbook Saxon Algebra 2

Answer by Edwin McCravy(20054)   (Show Source): You can put this solution on YOUR website!
a set of test scores is normally distributed with a mean of 74 and a standard deviation of 8. Between what two scores does the middle 95% of the data fall?

,



From the table we get that .025 of 2.5% of the data lies to the
left of z=-1.96, and .025 or 2.5% of the data lies to the
right of z=+1.96

To find the two x values that corresponds to z=-1.96 and z=+1.96  
we use the formula:



For z = -1.96

 



For z = +1.96

 



So the middle 95% of the scores lie between 
58.32 and 89.68.  Maybe you'd round those and
make it between 58 and 90.

Edwin
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