An organization has two cars, both the same model that are used by their two sales staff. On balance both travel about same amount of miles each month. On reading through the expenses claim for petrol from the two sales people the manager thinks that one of them is using more petrol than the other. Based on the amount of petrol claimed for and the miles travelled he tabulates the consumption rates, in miles per gallon, for the two sales people:
Use a Normal approximation of the Mann-Whitney U test to find if the driving styles of the two sales people differ.