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. Mean SD Hwy MPG, Automatic 22.92 5.29 26 Hwy MPG, Manual 27.88 5.01 26 n 35 25 15 automatic manual Hwy MPG upper bound: lower bound: mpg (please round to two decimal places) 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

Answer 1

Intl Automatic 22.92 5.29 manuch 27.88 we have ence between manual calceu at 987. (a for diffen average highway mileage & automatic Cars 2 let sample 1 represent the manual S Sample automatic car. then we find CI for (Mi-uz) Where aure population mean manuel & automatic cars ولا لا ل eesp. Six + S2² + nz :. (I is [(Ita) i to * te at 98% CI is 2.4 lower bound is (xi-xa-te* (27.88 - 22-92) - 2.4 * 1.429 - 1.53 Npper bound is cxi-tz tt * * - 127-88-22-92) +2.4 & 1-4 29 8.39

1.53 lower bound upper bound 1 Interpret can be g81. confident that the difference in average highway mirease & automatic cars contained within confidence intera Does your I provide significant evidence for difference in highway fuel efficiency of automatic manual crers 2 yes, since high way mileage cannot be negative.