10.4.1 .WP The manager of a fleet of automobiles is testing two brands of radial tires and assigns one tire of each brand at ran

Hello! You need to calculate a 99% confidence interval for the difference in mean lifespan between two tire brands. Each tested car was assigned one tire from each brand randomly on the rear wheels, allowing for paired sample analysis.       Brand 1  Brand 2  X₁-X₂      car 1:  36,925;  34,318;  2.607      car 2:  45,300;  42,280;  3.020      car 3:  36,240;  35,500;  0.740      car 4:  32,100;  31,950;  0.150      car 5:  37,210;  38,015;  -0.0805      car 6:  48,360;  47,800;  1.160      car 7:  38,200;  37,810;  0.390      car 8:  33,500;  33,215;  0.285      n= 8 The study variable is defined as Xd= X₁-X₂, where X₁ represents the tire lifespan (in km) from Brand 1 and X₂ represents Brand 2. Thus, Xd is the difference in tire lifespan. Xd~N(μd;δd²) (normality test p-value is 0.4640). For calculating the confidence interval, the best statistic is the Student's t using the following formula: t= (xd[bar] - μd)/(Sd/√n) ~t₍ₙ₋₁₎ sample mean: xd[bar]= 0.94 standard deviation: Sd= 1.29 = 3.355 xd[bar] ± *(Sd/√n) ⇒ 0.94 ± 3.355*(1.29/√8) [-0.65;2.54]km. The CI can be compared to bilateral hypothesis testing: H₀:μd=0 H₁:μd≠0 using significance level of 0.01. Since the confidence interval includes zero, we do not reject the null hypothesis, indicating no significant difference between the tire brands. Hope you have a fantastic day!