Graph Attack!

Graphs and data tables are very useful mathematical tools for a variety of reasons.  I particularly enjoy them because they can tell a story and offer a significant amount of information in a relatively straight forward way.  They are also a great way to organize information in order to get a better look at the bigger picture.

A Line Graph is used to track changes over periods of time.  A line graph is the preferred choice when the changes are smaller because they are easier to see.  You can also use line graphs to compare changes in multiple groups over a period of time.  

A Pie Chart is used when you are comparing parts of a whole. There is no way to use them to show changes over time.  They are simply a ratio comparison of specific data.

A Bar Graph can be used to compare things between different groups and is the preferred choice when comparing larger changes over time.  

When introducing Graphs to students and children it can be useful to also introduce data collection.  The best way to understand how to interpret a graph or chart is to learn how to collect and organize the data for one.  I have discovered a very efficient way to introduce data collection to a classroom:

1. Have each student think of something they want to learn about their classmates, for example: Favorite Food.
2. Next, determine the number of elements you want them to have for the set.
3. Show students how to make a T-chart or some other efficient chart to collect the data.
4. Have the students sit in a circle and pass their charts in the same direction.  Make sure the students take their time and everyone fills in a chart.
5. Show the students the options they have for graphs and have them choose their graphs.
6. Students create their graphs.
7. Everyone shares and practices reading each others graphs.

We are constantly exposed to graphs and data tables in the every day world.  Many times this is at the hands of marketers and advertisers.  There is usually an agenda behind the compilation of information being shared with us.  It is important that we are able to interpret the information and be able to spot and identify and biases and flaws.  This is the biggest reason it is important for students to learn about these concepts.  It is very easy to be swayed by a biased/skewed graph!