An experiment compared the adhesion of 2 types of paint, A and B, to 3 types of metal, 1, 2, and 3, used in automobiles. Thirty sheets of metal were used in the experiment: 10 of Metal 1, 10 of Metal 2, and 10 of Metal 3. Half of each metal type will receive paint A and the other half will receive paint B. The adhesion of the paints was measured, and the measures were compared. How many experimental units are in the experiment?

A. 2

B. 3

C. 10

D. 30

E. 60

There are 30 experimental units in the experiment, which are the 30: the thirty sheets of metal.

Explanation:

This table shows you how the experimental units, sheets of metal, were treated:

Metal 1 Metal 2 Metal 3 Total

Paint A 5 5 5 15

Paint B 5 5 5 15

Total 10 10 10 30

Fifteen sheets (units) were treated with paint A: 5 of metal 1, 5 of metal 2, and 5 of metal 3.

Fifteen sheets (units) were treated with paint B: 5 of metal 1, 5 of metal 2, and 5 of metal 3.