1. Independent And Dependent Variables The independent variable is the piece of information that the data collector controls or chooses. If time is included in the graph, it is always the independent variable because the data collector can control the time period he graphs. The dependent variable is the piece of information that the data collector can not control or measures. These are statements to help you decide what is the independent variable and the dependent variable. You decide_________( Independent variable ) You measure________(Dependent variable).When you make a graph, you always put the independent variable in the X axis. Then put the dependent variable in the Y axis. When you read a graph, the same rule applies.

2. Sample Problem This is a bar graph. At the X axis is the independent variable. It is the independent variable because you can pick what shows you want to graph. However, you can not control the number of people that enjoy that subject. That is the dependent variable. You decide the shows to graph, You measure how many people like them.

3. Practice Problems For the following problems, decide which piece of information is the independent variable and the dependent variable. 1.The number of elephants in selected African countries. 2.The number of ice creams a ice cream man sells. 3.The average price of a Marvel comic. You decide______________ You measure____________ Need more practice? Go to: http://www.texassciencecenter.org

4. Links Need more practice problems? Go to this site! http://texassciencecenter.org/tutorail/graphpractice.htm