Question 132766
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 grater than 10?
Use Excell to find the right-tail p-value.
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Ho: mu = 10
Ha: mu > 10 (Claim)
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Critical value for one-tail t-test with alpha = 1% and df=34: t = 2.326
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Test statistic: t(14.44) = (14.44-10)*[4.45/sqrt(35)] = 5.9027..
p-value = P(5.9027 < t < 10,with df=34) = 0.00000057596...
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Conclusion: Since p-value is less than 1%, reject Ho:
The test results support the Claim.
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Cheers,
Stan H.