Question 632481: A leasing firm claims that the mean number of miles driven annually, u , in its leased cars is less than 12800 miles. A random sample of 50 cars leased from this firm had a mean of 12499 annual miles driven. It is known that the population standard deviation of the number of miles driven in cars from this firm is 3140 miles. Is there support for the firm's claim at the 0.05 level of significance?
Perform a one-tailed test.
null hypothesis?
alternative hypothesis?
type of test statistic?
value of the test statistic?
the p-value?
Can we support the leasing firm’s claim that the mean number of miles driven annually is less than 12800 miles?
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! A leasing firm claims that the mean number of miles driven annually, u , in its leased cars is less than 12800 miles. A random sample of 50 cars leased from this firm had a mean of 12499 annual miles driven. It is known that the population standard deviation of the number of miles driven in cars from this firm is 3140 miles. Is there support for the firm's claim at the 0.05 level of significance?
Perform a one-tailed test.
null hypothesis?:::::::::Ho: u >= 12800
alternative hypothesis?::Ha: u < 12800 (claim)
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type of test statistic?::: z value
Note: Could be a t-value if your text calls for it.
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value of the test statistic?::
z(12499) = (12499-12800)/[3140/sqrt(50) = -0.6778
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the p-value = P(z < -0.6778) = 0.2489
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Can we support the leasing firm’s claim that the mean number of miles driven annually is less than 12800 miles?
NO, the p-value is greater than 5% so Ho cannot be rejected.
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Cheers,
Stan H.
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