Question 9 of 10 (1 point) Attempt 1 of 1 View question in a popup O th 32m Rema

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Question 9 of 10 (1 point) Attempt 1 of 1 View question in a popup O th 32m Remaining 10.3 Section Exercise 8 (calc) Brake wear: For a sample of 9 automobiles, the mileage (in 1000s of miles) at which the original front brake pads were worn to 9% of their original thickness was measured, as was the mileage at which the original rear brake pads were worn to 9% of their original thickness. The results were as follows: Car Rear Front 1 40.6 32.5 2 35.4 27.1 3 46.6 35.6 4 47.3 35.6 5 38.7 30.3 6 51.2 41.1 7 50.6 40.7 8 45.9 34.3 9 47.236.5 Send data Part: 0/2 Part 1 of 2 (a) Construct a 99.5% 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. A 99.5% confidence that the mean difference in lifetime between front and rear brake pads is Next Part

Explanation / Answer

Answer: The 99.5% Confidence interval that the mean difference in a life time between from and rear brake pad is : 8.170235 < µd < 11.78532

since

Sample size, n: 9
Difference Mean, d: 9.977778
Difference Standard Deviation, sd: 1.414901

Critical t: ±3.8325

Lower bound: 9.977778 - 3.8325*1.414901 = 8.170235

Upper bound: 9.977778 + 3.8325*1.414901 = 11.78532

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