Is there a difference in the average wear between the two brands at the 5% significance level? ...

     4. The green taxi co.   tested twenty tires, ten of brand F and ten of brand G. They assigned one of   each tired at random to a car and after 30,000 miles the tires were checked   for wear. Is there a difference in the average wear between the two brands at   the 5% significance level? The following data were obtained in millimeters of   wear. Car- BrandF - BrandG 1- 3.2- 3.1 2- 4.1- 3.9 3- 3.5 - 3.7 4- 2.9 - 3.3   5- 3.4 - 3.6 6- 3.7 - 3.8 7- 3.2 - 3.0 8- 3.8 - 3.6 9- 2.8 - 3.1 10- 3.9 -   4.1