<PRE><B>Question 325017</B>
A study by a bank compared the average savings of customers who were depositors for three years or less, with those who had been depositors for more than three years.  The results of a sample are:

                                  &lt;
                                  - 3 years    &gt; 3 years
Mean savings balance                $1200        $1250
Standard deviation                   $100         $150
Sample size                           10           15

 


	14.  Assuming that the financial officer wants to show that there is a difference in the average savings balance between the two classes of depositors, what is the null hypothesis? _____________________ 
Ho: u(&lt;3)-u(&gt;3) = 0
Ha: u(&lt;3)-u(&gt;3) is not 0
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	15.  For alpha = 0.05, what is the critical value of t? 
Using df = n1-1 + n2-1 = 23 I get +-invT(0.975,23) = +- 2.0687_____ 


	16.  What is the computed test statistic? t = -1_____ 
Using a TI-84 I get t = -1 on a 2-SampleZtest.

	17.  What is the p-value if alpha = .05 and the test statistic is 2.807?
p-value = 2*P(t &gt; 2.80 when df=23) = 2*tcdf(2.80,100,23) = 0.0102
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Cheers,
Stan H.
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