Rachel and Mitch own a café. They want to decide whether more staff are needed at certain times. On one day, Rachel records how long customers wait to be served at specific times after 9am. Write down the independent and dependent variables.

1. Understand the definitions: - **Independent Variable**: The variable that is changed or controlled in an experiment to test its effects on the dependent variable. It's what the researcher is investigating as a potential cause. - **Dependent Variable**: The variable being tested and measured in an experiment. Its value is expected to "depend" on the independent variable. 2. In this study, Rachel is observing if the waiting time *changes because of* the time of day. 3. The time of day ("Minutes after 9am") is the factor being investigated. Rachel is choosing the times to measure. This is the independent variable. 4. The "Waiting time" is what is being measured to see if it is affected. This is the dependent variable.