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An auto maker estimates that the mean gas mileage of its sport utility vehicle is 20 miles per gallon. A random sample of 8 such vehicles had a mean of 18 per gallon and a standard deviation of 5 miles per gallon. At á=0.05, can you reject the auto maker’s claim that the mean gas mileage of its sports

utility vehicle is 20 miles per gallon? Assume the population is normally distributed.

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3 answers

  1. You can use a t-test for this problem since the sample size is small.

    Using your data in the formula:
    t = (18 - 20)/(5/√8) = ?

    Finish the calculation.

    Using a t-table at 0.05 level of significance for a two-tailed test (the test is two-tailed because the alternative hypothesis would not specify a direction) at 7 degrees of freedom (df = n - 1 = 8 - 1 = 7), find your critical or cutoff value to reject the null. If the t-test statistic calculated above does not exceed the critical value you found in the t-table, you cannot reject the null. If the t-test statistic exceeds the critical value from the t-table, reject the null.

    I hope this will help get you started.

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  2. of 500 employee ,200 participating i n companies profit sharing plan (p),250 having major medical insurance coverage (m) and 50 find the probibility +will not be participant in either program

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  3. of 500 employee ,200 participating i n companies profit sharing plan (p),250 having major medical insurance coverage (m) and 50 participated in both program
    find the probibility will not be participant in either program

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