Test Review Scientific Method Variables and Graphing Test

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

What is a Variable? l l l 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.

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

Independent Variables l l 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.

Dependent Variables l l l 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.

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

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

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

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

3 of 10 Using Tables Title Heading Row Column

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

Using Tables 8 of 10 ? What percent of hardware problems relate to the drives and RAM? A 18. 5 % ? What would you do to decrease initial problems? A Send better instructions about the peripherals

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

Using Circle Graphs 12 of 12 Home 4 Construct a circle graph to show the following data about bald eagle populations in 1998 – When you are done click to see an example.