Find the sum or difference of 1/2x-8+1/2x-2

The tire wear for the right and left tires of the same car is given below. car 1 2 3 4 5 6 7 8 9 10 11 12 13 14 right 42 75 24 56 52 56 23 55 46 52 47 62 55 62 tire left 54 73 22 59 51 45 29 58 49 58 49 67 58 64 tire (a) give a point estimate for the difference between the mean wear right tires of all cars and the left tires of all such cars. (b) construct the 99% confidence interval based on these data for the difference. (c) test, at the 1% level of significance, the hypothesis mean wear right tires of all cars and the left tires of all such cars are different.