Comparing fuel economy in different cars

Introduction

Fuel consumption is an important consideration when seeking a car that produces low output of polluting gases. By looking at different makes and models of cars, you can determine which factors are important in affecting the fuel consumption, as measured by the number of miles the car will travel on one gallon of petrol.

Task

Using the data in Fuel economy in different cars from What Car? magazine, find out which factors in car design affect fuel consumption. Use the spreadsheet program Excel to draw a graph that shows whether there is a correlation (relationship) between the information about a car and its fuel consumption. Sort the data so that the cars are in order of their fuel consumption. The one with the highest consumption is at the top of the list.

Method

1. Select all the data. Click on the empty cell next to the A column.

2. Click 'Data' on the toolbar and select 'Sort' on the drop-down menu.

3. Choose to sort on column G (miles/gallon). Make sure you select the box that says there is a column heading. Then click 'OK'.

4. The data will now be rearranged into the right order. Choose a factor that you want to compare with fuel consumption (miles/gallon). Select the column by clicking on the letter at the top. Press the 'Control' key at the same time as clicking on column G (miles/gallon).

Results

1. Now that you have sorted the data, select the graph wizard and choose 'XY Scatter'.

2. Follow the steps outlined in the wizard.

3. When the graph is drawn, add titles and labels.

Conclusions

1. What does the graph show you?

2. Is there a good correlation between the factor and the fuel consumption?

3. Which are the most important factors in conserving fuel?

4. Are there any cars that are very different from the general trend?

Follow-up work

You may find that the diesel cars, for example, show a different trend to the other types. To check this, you can filter out the petrol cars.

1. To filter, first select 'Data' then 'Filter'.

2. Choose 'Autofilter'. Arrows will appear on the top of each column.

3. Select the 'fuel type' column.

4. Filter petrol.

5. Redraw your graphs now that you only have petrol engines in the data. Does this make the correlation closer?