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.

What is the mean height for the grass used as a control?
2 cm
4 cm
6 cm
12 cm

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.

What is the mean height for the grass used as a control?
2 cm
4 cm
6 cm
12 cm