Question

dr. flora is doing an experiment to test which type of fertilizer makes her roses grow the fastest. she separates 12 rosebushes into three equal groups and measures their height. she gives one group of rosebushes fertilizer a, she gives the second group fertilizer b, and she does not give fertilizer to the third group. she keeps everything else about the rosebushes environment the same, including the amount of water and sunlight provided. after a month, dr. flora measures the height of the rosebushes in all three groups. her results are shown below.

	average growth of roses
fertilizer b	12 cm
no fertilizer	5 cm

based on dr. floras results, which of the following can she conclude?
a. both fertilizer a and fertilizer b cause roses to grow at an increased rate.
b. fertilizer b causes roses to live longer than fertilizer a.
c. fertilizer a causes roses to die at an increased rate.
d. neither fertilizer a nor fertilizer b affects the growth rate of roses.

Explanation:

The average growth of roses with no fertilizer is 5 cm. With fertilizer A, it's 8 cm and with fertilizer B, it's 12 cm. Since the growth with both fertilizers is more than without fertilizer, both fertilizers increase the growth rate.

Answer:

A. Both fertilizer A and fertilizer B cause roses to grow at an increased rate.