for a sample of 9 automobiles, the mileage (in 1000s of miles) at which the original front brake pads were worn to 10% of their original thickness was measured, as was the mileage at which the original rear brake pads were worn to 10% of their original thickness. The results were as follows: Car Rear Front 1 41.2 32.2 2 36.3 27.2 3 45.8 34.7 4 46.6 37.3 5 39.6 30.7 6 52.3 40.5 7 51.7 41.0 8 46.3 33.8 9 47.4 36.8 a)Construct a 99.8% confidence interval for the difference in mean lifetime between the front and rear brake pads. Let d represent the mileage of the rear pads minus the mileage of the front ones. Round the answers to at least two decimal places. b)Because the confidence interval (contains/does not contain) values above 10 (in 1000s of miles), it (contradicts/does not contradict) the claim that the mean lifetime for rear brake pads is more than 10,000 miles more than the mean lifetime for front brake pads.
for a sample of 9 automobiles, the mileage (in 1000s of miles) at which the original front brake pads were worn to 10% of their original thickness was measured, as was the mileage at which the original rear brake pads were worn to 10% of their original thickness. The results were as follows:
Car | Rear | Front |
1 | 41.2 | 32.2 |
2 | 36.3 | 27.2 |
3 | 45.8 | 34.7 |
4 | 46.6 | 37.3 |
5 | 39.6 | 30.7 |
6 | 52.3 | 40.5 |
7 | 51.7 | 41.0 |
8 | 46.3 | 33.8 |
9 | 47.4 | 36.8 |
a)Construct a 99.8% confidence interval for the difference in mean lifetime between the front and rear brake pads. Let d represent the mileage of the rear pads minus the mileage of the front ones. Round the answers to at least two decimal places.
b)Because the confidence interval (contains/does not contain) values above 10 (in 1000s of miles), it (contradicts/does not contradict) the claim that the mean lifetime for rear brake pads is more than 10,000 miles more than the mean lifetime for front brake pads.
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