NJ State Partol would like to know if the mean speed that drivers drive in I-80 is faster than I-280. They gather following sample information and ask students to investigate this matter using .05 significance level.
I-80: Sample mean- 68 mph, Population standard deviation- 12 mph, sample size 112
I-280: Sample mean- 70 mph, population standard deviation- 14 mph, sample size 85