Solve the following:
Q: Shortly after their graduation, John and Mary bought two used vehicles. To satisfy their curiousity, they started to record their kilometrage each time they filled their gas tanks. After ten weeks, their records show the following numbers of kilometres per litre.
Mary: 17, 19, 16, 15, 18, 18, 20, 22, 15, 15
Mean= 17.5 Standard Deviation= 2.37
John: 9, 7, 16, 20, 23, 25, 29, 13, 15, 18
Mean= 17.5 Standard Deviation= 6.96
Interpret these results.