Question

A leasing firm claims that the mean number of miles driven annually, μ, in its leased cars is less than 12700 miles. A random sample of 25 cars leased from this firm had a mean of 12031 annual miles driven. It is known that the population standard deviation of the number of miles driven in cars from this firm is 2800 miles. Assume that the population is normally distributed. Is there support for the firm's claim at the 0.01 level of significance? Perform a one-tailed test. Then fill in the table below. Carry your intermediate computations to at least three decimal places, and round your responses as specified in the table. (If necessary, consult a list of formulas.)

The null hypothesis: H0: The alternative hypothesis: H1: The type of test statistic: (Choose one)ZtChi squareF The value of the test statistic: (Round to at least three decimal places.) The p-value: (Round to at least three decimal places.) Can we support the leasing firm's claim that the mean number of miles driven annually is less than 12700 miles? Yes No

Answer 1

The null hypothesis:	H0: = 12700
The alternative hypothesis:	H1:   < 12700
The type of test statistic:	(Choose one)ZtChi squareF	Zt
The value of the test statistic: (Round to at least three decimal places.)	-1.195
The p-value: (Round to at least three decimal places.)	0.122
Can we support the leasing firm's claim that the mean number of miles driven annually is less than 12700 miles?			No

here given is    = 12700 , X bar = 12031 ,   =2800 , =0.01 , Z = -2.33

we are using Z test statistics for sample test

Z = (x bar - ) //  n  

we got Z > Z so we failed to reject H0 so We can not support the leasing firm's claim that the mean number of miles driven annually is less than 12700 miles