d. Assuming that the speeds are from normally distributed populations, test the claim that the mean speed on the northbound lanes is equal to the mean speed on the southbound lanes. Based on the result from part (c), does it appear that this hypothesis test is likely to be valid?

Highway 405 North: 68 68 72 73 65 74 73 72 68 65 65 73 66 71 68 74 66 71 65 73 Highway 405 South: 59 75 70 56 66 75 68 75 62 72 60 73 61 75 58 74 60 73 58 75