Two popular brands of tires for tractor trailers are the

Last updated: 5/23/2023

Two popular brands of tires for tractor trailers are the Puma and the Eternal Kala is a buyer for a major shipping company and wants to estimate the difference between the mean distance in thousands of km driven on Puma tires before they need to be replaced and the mean distance in thousands of km driven on Eternal tires before they need to be replaced In the company s testing lab Kala tests a random sample of 14 Puma tires and a random sample of 15 Eternal tires These samples are chosen independently For each tire she logs the distance driven in thousands of km before the tire would need to be replaced These data are shown in the table Puma 56 5 57 0 49 1 60 5 54 3 61 0 51 4 51 3 53 8 53 0 47 7 47 6 57 8 57 6 Distances in thousands of km Eternal 57 0 55 5 51 8 58 7 60 5 53 4 44 9 34 1 57 8 38 8 52 0 49 9 31 5 56 8 54 0 Send data to calculator V Assume that the two populations of distances driven are approximately normally distributed Let be the population mean distance in thousands of km driven on Puma tires before they need to be replaced Let be the population mean distance in thousands of km driven on Eternal tires before they need to be replaced Construct a 95 confidence interval for the difference Then find the lower and upper limit of the 95 confidence interval Carry your intermediate computations to three or more decimal places Round your answers to two or more decimal places If necessary consult a list of formulas Lower limit Upper limit X M