In an experiment to test whether fertilizer affects plant height, what is the independent variable?

In an experiment to test whether fertilizer affects plant height, what is the independent variable?

• A. Plant height
• B. Type of plant
• C. Amount of fertilizer
• D. Soil color

Answer: (C)

The independent variable is the amount of fertilizer because you deliberately change this factor to see how it affects the plants. In an experiment, the variable you modify is what you’re testing to see if it causes a change in another variable, which here is the plant height. Plant height is what you measure to determine the fertilizer’s effect, so it’s the dependent variable. The type of plant or soil color aren’t being varied to test the fertilizer’s impact, so they’re not the factors you’re examining in this setup.

The independent variable is the amount of fertilizer because you deliberately change this factor to see how it affects the plants. In an experiment, the variable you modify is what you’re testing to see if it causes a change in another variable, which here is the plant height. Plant height is what you measure to determine the fertilizer’s effect, so it’s the dependent variable. The type of plant or soil color aren’t being varied to test the fertilizer’s impact, so they’re not the factors you’re examining in this setup.