Motor Trend magazine collected the horsepower and mileage for 32 cars in the 1973-74 model year. To see if there is any relationship between horsepower and mileage, I construct a scatterplot of the two variables.

According to the above graph, it can be clearly seen that the horse power of the engine (hp) increases, the mileage (mpg) reduces. So we can say there is a negative association between  horse power of the engine and the mileage. Further, when looking at the fit, I would say the quadratic approximation might be the good one.