> I'm really confused by this data. How could the average cost of the most expensive model be less than the cost of the most expensive brand? It's because the

> I'm really confused by this data. How could the average cost of the most expensive model be less than the cost of the most expensive brand? It's because the brand estimates are not based on actual costs, but only on oil changes: “In order to estimate annual maintenance costs, we found the amount spent on every two oil changes (as oil changes are generally done every six months).” Yet the actual oil change intervals for at least BMW, Mercedes, Audi, and Volvo are between once a year and once every two years, or after between 7500 and 15000 miles, depending on the brand and model.