Question

A student wants to test the hypothesis that fertilizer improves the growth rate of grass seeds. To test this hypothesis, the student put the same amount of grass seed in 3 containers with the same type of soil. The student measured the growth at the end of the week. All plants received equal amounts of water and sunlight. If you were asked to graph this data, what would you place on the x-axis?

Answer 1

As the student is trying to see the effects of fertilizer on the growth rate of seeds, then the variable on the x-axis should be the independent variable, which is the amount of fertilizer placed. The growth depends on the fertilizer, so it is the dependent variable.