Independent variable?

Okay, So I wanted to test the hypothesis that fertilizer improves the growth rate of grass seeds. To test this hypothesis, I put the same amount of grass seed in 3 containers with the same type of soil. Then, I measured the growth at the end of the week. All plants received equal amounts of water and sunlight. Im sorta confused though..What was the independent variable in this? Is it the fertilizer?|||The fertilizer is the independent variable (also called the manipulated variable) in this situation.





Water, soil, pot size were held constant so were not variables in this situation but could also be considered independent variables if you changed/manipulated them for each trial.





The height of the grass is the dependent variable (also called the responding variable).|||You should have added equal amounts of different fertilizer to the grass seeds. The fertilizer is the experimental variable. In graphing the data you received you have an independent variable and a dependent variable. In your case the amount of fertilizer added is the independent variable and the amount of growth is the dependent variable.