Question 455995: Faced with rising fax costs, a firm issued a guideline that any transmission of 10 pages or more should be sent by 2-day mail instead. Exceptions are allowed, but they want the average to be 10 or below. The firm examined 100 randomly chosen fax transmissions during the next year, yielding a sample mean of 10.2 with a standard deviation of 1.1 pages. At the .05 level of significance, is the true mean greater than 10? Explain your decision.
I'm not getting this work out correctly in excel using megastat. Can you please help me with the steps? Thank you for your for help
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! Faced with rising fax costs, a firm issued a guideline that transmissions of 10 pages or more should be sent by 2-day mail instead. Exceptions are allowed, but they want the average to be 10 or below.
The firm examined 35 randomly chosen fax transmissions during the next year, yielding a sample mean of 14.44 with a standard deviation of 4.45 pages.
(a) At the .01 level of significance,is the true mean greater than 10?
Ho: mu = 10
Ha: mu > 10
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t(14.44) = (14.44-10)/[4.45/sqrt(35)] = 4.44*sqrt(35)/4.45 = 5.9027...
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p-value = P(t > 5.9027 when df = 34) = tcdf(5.9027,100,34) = 0.0000005760
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Since the p-value is far less than alpha=1%, hasten to reject Ho.
The test gives strong statistical evidence that the mean
is not 10.
You might conclude that the mean is greater than 10 since that
is the alternative hypothesis.
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Cheers,
Stan H.
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