Question

an experiment will be conducted in which 20 pepper plants are randomly assigned to two groups. the plants in group 1 will receive the current fertilizer, fertilizer a, and the plants in group 2 will receive a new fertilizer, fertilizer b. all other growing conditions, including amount of sunlight and water, will be kept the same for the two groups. the growth of the pepper plants will be compared for the two groups. what are the experimental units in this experiment?
a the two types of fertilizer
b the sunlight and amount of water
c the 10 plants in group 1
d the 10 plants in group 2
e the 20 plants in the two groups

Explanation:

In an experiment, the experimental units are the entities to which the treatments are applied. Here, the treatments (Fertilizer A and Fertilizer B) are applied to the pepper plants. All 20 plants (in both groups) are the ones receiving the treatments (even though divided into two groups for different fertilizers).

• Option A: The two types of fertilizer are the treatments, not the experimental units.
• Option B: Sunlight and water are controlled variables (kept the same), not experimental units.
• Options C and D: Each group's plants alone don't represent all experimental units as the experiment involves both groups.
• Option E: The 20 plants (as a whole, with each plant being an individual unit getting either Fertilizer A or B) are the experimental units.

Answer:

E. The 20 plants in the two groups