Random Samples of 15 Model I Cars and 13 Model $\quad 70,60,80,75,81,73,80,90,82,93,89,95,91,88,90$

Essay

Random samples of 15 Model I cars and 13 Model II cars were obtained and the number of miles (in thousands) that each lasted from new until the car was "junked" was recorded.
Model I: $\quad 70,60,80,75,81,73,80,90,82,93,89,95,91,88,90$
Model II: $\quad 88,80,95,105,90,99,93,88,95,102,98,95,91$
Test the null hypothesis that the two models have the same average life expectancy against the alternative hypothesis that they do not have the same average life expectancy. Use $\alpha=0.01$ .