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What Kind of Graph Should I Use?

Objective: Students will utilize various types of graphs, including pie (circle) graph, pictograph, box-and-whisker plot, and stem and leaf plot. Students will understand when to use each graph appropriately. Students will also create a pie (circle) graph and a pictograph using given information.

Graphs

Graphs are an important way to visualize the data collected. Many people can grasp the overall meaning of a point being made by looking at the information in picture form.

For example, we can read about the many people who died in the Holocaust, but we can get a better grasp of how widespread the people groups were by looking at this pie (circle) graph.

pie graph Holocaust deaths.PNG

Pie Graph or Circle Graph

People love pie or circle graphs because they are a great visual. These graphs are beneficial when you want to show percentage distributions.

To put data into a pie graph, you must decide what the categories are that you are testing then find the percentage of the circle that each category takes up.

To find each percentage, you will need to find the sum of all of the parts and then find the fraction that each part is to the sum. After you have each fraction or percentage (these should equal 100%), you will then see how much of the circle needs to be shaded by multiplying the fraction times 360 (the number of degrees in a circle). This will tell you how much of that circle will be shaded for each part.

Pie charts can be very helpful to businesses. Watch the following video to see a good example of how pie (circle) graphs are used.

Now, let's see how to use Word or Excel to make our own pie chart. Click on the following link and make sure to write the steps down for future references. Then use your notes to make your own pie chart with the instructions provided later in the lesson.

Assignment: Use the instructions from the video to create a pie (circle) graph using the following information:

Title: Birds I've Seen

Segments:

Hawks 45%
Owls 20%
Blue Jays 18%
Robins 6%
Crows 11%

**Save this pie chart and have it ready to upload as part of your daily work.

Pictographs

This type of graph can be a difficult one to apply to a science fair project.

graph pictograph fruit.PNG

Pictographs are easy to read and can be quite colorful but usually give us information or show us opinions. This is not helpful when doing an experiment.

The pictograph below shows how much money each store made from pumpkin sales which would not work for a science fair project, but the same concept could be used if the project was testing different brands or species of pumpkin plants to see which yielded the most pumpkins. Even though pictographs may not be very useful for a science fair experiment, knowing how to read this kind of graph is still important.

Now, let's see how to use Word or Excel to make our own pictograph. Watch the following video, take notes of the steps that should be used, then use your notes to make your own pictograph with the information provided later in the lesson.

Assignment: Use the instructions from the video to create a pictograph using the following information:

Title: Sports People Prefer

Column headings:

Sport
Number of people

Categories under sports:

Baseball
Football
Basketball
Golf
Soccer

Ask 10 people you know to give you their number-one choice from the list and keep a tally of their answers. Choose your own icons to represent people or the individual sport.

**Save this pictograph and have it ready to upload as part of your daily work.

Box-and-Whisker Plot

box and whisker plot.gif

Another interesting possibility is the box-and-whisker plot. This graph emphasizes the spread of the data from the median or midpoint of the numbers involved. As you watch the video see if you can figure out how it got its name.

Stem and Leaf Plot

Now let's look at the stem and leaf plot. This is a different way of visualizing data which shows all the numbers gathered and how they are distributed. No information is lost and their distribution is obvious.

For example, a teacher may use this stem and leaf plot to visualize the success of students on a test. It would be easy to see if the majority of the students did well on the test or if the material needed to be retaught.