Question 202384
to answer this question, it helps to have a graphing calculator, or to have an online calculator.
the online calculator I used is at this web address.
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http://davidmlane.com/hyperstat/z_table.html
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for this problem, the upper half of the calculator is used.
enter the mean (100) and enter the sd (15).
click on between and enter the values you want.
first value is between 70 and 85.
answer is 13.5905% which the calculator shows you.
second value is between 100 and 115.
answer is 34.1345% which the calculator shows you.