## Item CR023005: In an experiment involving two variables (X and Y) that could affect the outcome of the experiment, changing X and keeping Y constant allows you to find out the effect of X on the outcome of the experiment.

A student thinks that there are two variables (X and Y) that may affect the result of her experiment.

She decides to change only variable X and let variable Y stay the same.

What can the student find out about the effects of variables X and Y?

- If variable X affects the result of her experiment.
- If variable Y affects the result of her experiment.
- If both variables X and Y affect the result of her experiment.
- She cannot find out if either variable X or variable Y affects the result of her experiment.

- Distribution of Responses

- Students Responding Correctly

Group | Correct | Total | Percent |
---|---|---|---|

Overall | 1187 | 2371 | 50% |

Grades | |||

6–8 | 541 | 1288 | 42% |

9–12 | 642 | 1074 | 60% |

Gender | |||

Male | 604 | 1162 | 52% |

Female | 565 | 1173 | 48% |

Primary Language | |||

English | 1069 | 2083 | 51% |

Other | 89 | 227 | 39% |