Hypothesis test for single mean.
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 throughout 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?
b. utilize Excel to find the right-tail p-value.
N = 35 M= 14.44, STD DEV 4.45,
H0 less than or equal to10
H1>10
Z0.01= 2.326
(10-14.44)/(4.45 /sq root 35)= 0.44/0.7521= -0.5850
P (Z less than equal to - 0.5850)=-0.7207
1-0.7207= 0.2800
H1 alternative is accepted.
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Confidence interval - mean
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99%
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confidence level
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14.44
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mean
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4.45
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std. dev.
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35
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n
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2.576
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z
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1.938
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half-width
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16.378
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upper confidence limit
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12.502
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lower confidence limit
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