Car Fuel Efficiency History

Questions:

1. What is the overall trend in fuel economy over time?

2. Is there a difference in fuel economy by the origin of the car produced? If so, is there an underlying difference in the type of cars manufactured in each?

3. Is there a difference in fuel economy by the origin of the car produced? If so, is there an underlying difference in the type of cars manufactured in each?

Strategy:

To answer the first question concerning trends in fuel economy over time, it has to be assumed the data is based on averages for each make and model of car listed in the dataset. Therefore, an average for the year is based on averages for each individual car. We do not know if or how many outliers existed in the original data or how much the data skewed to one side for each make and model. To avoid the average of averages dilemma it is best to use a Confidence Interval to state the Differences in Averages between the years of 1970 to 1982. A Normal Distribution is assumed because the median and average of averages are so close together.

Histograms were used to help prove the assumption the data is normally distributed when it comes to fuel economy. Overall as the data is displayed by year during the animation it can be seen the data usually follows a bell curve that resembles a normal distribution.

By separating the countries into their own histograms, Question 2 is answered. By connecting this chart to the animation for the all makes and models histogram, (pictured above), it can be seen the USA trails the other two countries when it comes to producing fuel efficient cars.

To answer Question 3, the page was divided into two colors to separate questions 1 and 2 from question 3. It helps the user concentrate on one section of the animation at a time. Questions 1 and 2 were grouped together because they both help show the a normal distribution. The Year 1982 marked lines and shaded areas were added to help the user visualize where the data is traveling towards.

All years represented:

Only year 1982 represented from animation:

Here is a link to my working model: Fuel Efficiency