1. GRAPHING NOTES Understanding and constructing graphs

2. Purpose of a Graph Compares how one variable changes with respect to another variable Compares how one variable changes with respect to another variable May indicate a cause and effect relationship May indicate a cause and effect relationship

3. Parts of a Graph Title: describes information a graph contains Title: describes information a graph contains Source: where information came from Source: where information came from Scale: value of one “box” on graph, number of units Scale: value of one “box” on graph, number of units Units: measurement in which data was recorded (inches, mm) Units: measurement in which data was recorded (inches, mm)

4. Parts of a graph Legend: explanation of symbols used, also called a key Legend: explanation of symbols used, also called a key X-axis: horizontal reference line, usually independent variable X-axis: horizontal reference line, usually independent variable Y-axis: vertical reference line, usually dependent variable Y-axis: vertical reference line, usually dependent variable

5. Types of graphs Line graph: one quantitly depends on changes in another. Values of numbers are plotted and connected with a line. May be used to predict future quantities Line graph: one quantitly depends on changes in another. Values of numbers are plotted and connected with a line. May be used to predict future quantities

6. Typical line graph

7. Graph with multiple lines

8. Types of Graphs Bar Graph: Bars represent quantities. Used to compare related data side by side or track multiple categories Bar Graph: Bars represent quantities. Used to compare related data side by side or track multiple categories Pie or circle graph: Shows portions of a whole, based on 100% Pie or circle graph: Shows portions of a whole, based on 100%

9. Typical Bar Graph

10. Typical Pie Graph

11. How to read or construct a graph Title Title Label and determine scale of axes Label and determine scale of axes Determine units Determine units Look at trends, patterns and relationships in the data represented Look at trends, patterns and relationships in the data represented