Original Project
Control of Variables
If more than one variable changes at the same time in an experiment, the outcome of the experiment may not be cl…
Item CR030001: In an experiment involving three variables (X, Y, and Z) that could affect the outcome of the experiment, changing X and keeping Y and Z constant allows you find out the effect of X on the outcome of the experiment.
A student thinks that there are three variables (X, Y and Z) that may affect the result of her experiment.
She decides to change only variable X, and let variables Y and Z stay the same.
What is the student trying to find out?
- If variable X affects the result of her experiment.
- If variables X and Y affect the result of her experiment.
- If variables Y and Z affect the result of her experiment.
- If variables X, Y, and Z affect the result of her experiment.
- Distribution of Responses
- Students Responding Correctly
| Group | Correct | Total | Percent |
|---|---|---|---|
| Overall | 1721 | 2556 | 67% |
| Grades | |||
| 6–8 | 790 | 1377 | 57% |
| 9–12 | 922 | 1165 | 79% |
| Gender | |||
| Male | 803 | 1257 | 64% |
| Female | 902 | 1277 | 71% |
| Primary Language | |||
| English | 1517 | 2203 | 69% |
| Other | 175 | 314 | 56% |