Final answer:
The type of fertilizer is the independent variable in an experiment testing its effect on coffee bean production, while the number of coffee beans is the dependent variable. Control variables, such as water and sunlight, must be kept constant.
Step-by-step explanation:
In the context of the student's question regarding whether the type of fertilizer affects the number of coffee beans that grow, the type of fertilizer is the independent variable. This is because it is the variable that is purposely altered by the researcher to examine its impact on the number of coffee beans, which is the dependent variable. In other words, the dependent variable is what the experimenter measures or is interested in predicting, and it is affected by changes to the independent variable.
In an effective experiment, other factors that might affect the dependent variable should be controlled. These include environmental conditions like the amount of water, the amount of sunshine, and temperature. These are known as control variables. Having a control group, where no fertilizer is added, is essential to compare and establish the effects of different fertilizer types on coffee bean production. This helps isolate the effects of the independent variable on the dependent variable.
So, in summary, in an experiment designed to test how fertilizer affects plant growth, the type of fertilizer is the independent variable, the growth (as measured by the number of coffee beans) is the dependent variable, and conditions like water and sun exposure are control variables.