Hybrid vehicles were a notion that environmentalists spoke about as a concept, which could increase gas mileage of vehicles, and conserve consumption of fossil fuels. According to Wikipedia, "Today's hybrid cars or hybrid electric vehicles are automobiles powered by internal combustion engines, but also equipped with batteries recharged during driving and an electric motor to assist with power demand" (2005). "'Hybrids do not necessarily have to be plugged in, yet still deliver superior mileage and are environmentally-friendly alternatives to traditional internal combustion vehicles"(2005). With ever increasing costs of gasoline, we must ask, are hybrid vehicles the future of internal combustion vehicles? Studying the relationship between petroleum costs and increasing sales of hybrid vehicles will give us some insight on the ever growing demand of these vehicles in respect to gasoline prices. Since the debut of the Honda Insight in 1999, increasing costs of gasoline has been a strong factor in the increasing sales of hybrid vehicles.

Utilizing regression analysis, Team A will forecast the future sales of hybrid vehicles and how they may be a significant portion of future automobiles as compared to the increasing costs of petroleum.

To ensure the data has a strong correlation and will be accurate, we will begin by calculating the coefficient of correlation. Once we have established a strong correlation, we will forecast future sales of hybrid vehicles utilizing a four step process as outlined by Business Statistics: "(1) determine the equation of the line that best fits the data, (2) estimate the value of one variable based on another, (3) measure the error in our estimate, and (4) establish confidence and prediction intervals for our estimate" (pp 139, 2005).

The first step of the process is to develop an equation to express the linear or straight line relationship between the two...