Automobile company compares two different types of front bumpers for their new model by driving sample cars into a concrete wall at 20miles per hour. The response is the amount of damage to the car, as measured by the repair costs, in hundreds of dollars. Due to the costs, the study uses only six cars, obtaining results for three bumpers of each type. The results are in the table. Conduct statistical inference (95% confidence interval or significance test with significance level 0.05) about the difference between the population means, using software if you wish. Can you conclude that the mean is higher for one bumper type?
Bumper A Bumper B
11.......... 1
15.......... 3
13.......... 4