The table provides summary statistics on highway fuel economy of cars manufactur

Question

The table provides summary statistics on highway fuel economy of cars manufactured in 2012 (from Exercise 5.32). Use these statistics to calculate a 98% confidence interval for the difference between average HIGHWAY mileage of manual and automatic cars, and interpret this interval in the context of the data. You are estimating mu_automatic - mu_manual USE YOUR TI CALCULATOR. lower bound: mpg (please round to two decimal places) upper bound mpg please round to two decimal places) Interpret your confidence interval in the context of the problem: We can be 98% confident that the difference in average highway mileage of manual and automatic cars is contained within our confidence interval 98% of manual and automatic cars will have a difference in highway mileage that falls within our confidence interval We can be 98% confident that our confidence interval contains 98% of the differences in average highway mileage of the cars in our sample Does your confidence interval provide significant evidence for a difference in the highway fuel efficiency of automatic versus manual cars? Explain. no, since negative highway mileage doesn't make sense yes, since 0 is not contained within our confidence interval yes, since highway mileage cannot be negative no, since 0 is not contained within our confidence interval

Explanation / Answer

Sol:

z for 98% CI= 2.33

Difference between means:
M1-M2=27.88-22.92=4.96
sd=10.089; se=1.4289
98% CI of difference:
1.6359 <4.96< 8.2841

lower bound:1.64

upper bound=8.28

Diff in means =4.96 which is the interval range

So

Answer A which is

we can be 98% confident that the diff in average highway mileage of manual and automatic cars is contained withiin our confidnce inetrval

SOlution2:

Yes,since 0 not contained within our confidence interval

Answer B

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