1. Bell Ringer
When completing an experiment, you are testing your hypothesis. What are the three kinds of variables that you need to identify in your experiments?
A: independent, controlled, and dependent
B: independent, dependent, and identical
What is the independent variable?
A: the variable that you purposely manipulate
B: the variable that is being observed
C: the variable that is not changed

2. What is the controlled variable?
A: the variable that you purposely manipulate
B: the variable that is being observed
C: the variable that is not changed
How many independent variables can you have during an experiment?
A: 1
B: 2
C: as many as you would like
D: the same amount as the number of controlled variables
How many controls can you have in an experiment?
A: 0
B: 1
C: 2
D: as many as you would like

3. Types of Graph
And when to use them!

4. Bar Graph

5. Bar Graph
Used to compare amounts in data that represent different categories (discrete data sets)
Often times “category” is plotted on X-axis, number values) on the Y-axis
Often used incorrectly to graph data with continuous X variables

6. Line Graph

7. Line Graph Used to show trends
Variable plotted on X (bottom) musts be continuous
Common type is “time series” where X = time
CANNOT be used to graph data where X is discrete

8. Scatterplot

9. Scatterplot Used to show relationships between variables
X variable must be continuous
If one variable is believed to cause or explain changes in the other, that variable is plotted on the X

10. Histogram

11. Histogram Used when discrete X is converted to categories (“bins”)
Y represents frequency of data within each “bin”

12. Pie Chart

13. Pie Chart Used for same kind of data as bar chart
Each slice = data category
Slice size shows relative proportion of observations within each category

14. Summary: Types of Graph
Graph type
Use
Line graph
Connects dots with lines
Used for continuous X data
Show patterns or trends
If time = X, time-series graph
Scatterplot
Display relationship between variables
Line of Best Fit or Trend Line
Bar graph
Used to show patterns
Should only be used when X data are categorical or discreet

15. Graph type
Description
Histogram
Similar to bar graph, but used when continuous X data are converted to categories
Pie chart
Compares small number of categories.
Works best if values are very different.
If similar, should label pie segments with actual values