1. Graphing
Section 1.3

2. Why use graphs?
Graph- used to make data easier to read and understand- shows patterns and trends

3. What is a graph? Visual display of information or data
X-axis- horizontal- independent variable
Y-axis- vertical- dependent variable
Must have labels for each axis, a title, and units if appropriate
You must select the proper scale.
Don’t make the scale too large or too small
Make sure you can read the data easily

4. Examples of Proper Scale and Improper Scale

5. Types of Graphs Line, Bar, Pie Line Graph
Shows relationship between dependent and independent variable- often shows change over time
Can compare more than one event as long as scale is the same
Used most often in this class and science in general

6. Reading Line Graphs

7. Reading Line Graphs Linear Relationships- makes a straight line
both sets of numbers increase
both sets of numbers decrease
one set increases while the other set decreases
one set of numbers increases while the other stays exactly the same
one set of numbers decreases while the other stays exactly the same.

8. Reading Graphs Interpolation- reading between data points
Extrapolation- reading beyond data points
Less reliable than Interpolation
Maybe something unexpected occurs after known data points

9. Problems with graphs You might use the wrong scale
Don’t put two different units on the same graph- like Celsius and Fahrenheit or Celsius and Kelvin
Can be used to distort data- maybe the scale is manipulated to make something seem worse than it is or not as bad as it is

10. Bar Graph + Circle/ Pie Bar: Compare information collected by counting
Example: Comparison of how many in this class like which cookies. Try it.
Circle/Pie: Shows how something can be broken down into parts
Shows percents

11. Making Circle/Pie Graphs
Use our cookie data:
Determine % of each category
Multiply % by 360
Gives you degrees of the circle
Make Graph- will need protractor and compass