1. Test Review: Scientific Method, Variables, and Graphing
Test Monday 9/14/09

2. What is a Variable? Simply, something that varies.
Specifically, variables represent persons or objects that can be manipulated, controlled, or merely measured for the sake of research.
Variation: How much a variable varies. Those with little variation are called constants.

3. Examples of Variables
In the recent GOP sweep of the House and Senate, variables (or factors) that may have played a part would include:
Voter Turnout
Party Message
# of Open Seats
Redistricting
# of Incumbents
Wellstone Funeral

4. Independent Variables
These variables are ones that are more or less controlled.
Scientists manipulate these variables as they see fit.
They still vary, but the variation is relatively known or taken into account.
Often there are many in a given study.

5. Dependent Variables
Dependent variables are not controlled or manipulated in any way, but instead are simply measured or registered.
These vary in relation to the independent variables, and while results can be predicted, the data is always measured.
There can be any number of dependent variables, but usually there is one to isolate reason for variation.

6. Independent V. Dependent
Intentionally manipulated
Controlled
Vary at known rate
Cause
Intentionally left alone
Measured
Vary at unknown rate
Effect

7. Example: What affects a student’s arrival to class?
Variables:
Type of School
Liberals Arts v. University
Type of Student
Athlete? Gender? GPA?
Time
Bedtime, Waking, Arrival
Mode of Transportation

8. Graphing Dependent v. Independent Variables
The dependent variable is placed on the y-axis, while the independent variable is placed on the x-axis.
Example: Cell Phone Subscribers.
What is wrong with this title?

9. The title is incorrect
Title should be:
“Cell phone users vs. ear”

10. 3 of 10
Using Tables
Title
Column
Heading
Row

11. Using Tables Which system has the most hardware problems?
7 of 10
Using Tables
Which system has the most hardware problems?
Video
Users have the most difficulty with which system?
Peripherals

12. 8 of 10
Using Tables
What percent of hardware problems relate to the drives and RAM?
18.5 %
What would you do to decrease initial problems?
Send better instructions about the peripherals

13. Using Circle Graphs What percent prefer pizza or hamburgers?
8 of 12
Using Circle Graphs
What percent prefer pizza or hamburgers?
63%
What is the least popular menu item?
Hot Dogs

14. 12 of 12
Using Circle Graphs
Home
Construct a circle graph to show the following data about bald eagle populations in 1998
When you are done click to see an example.