Detergent manufacturers frequently make claims about the effectiveness of their products. A consumer-protection service decided to test the five best selling brands of detergent, where each manufacturer claims that its product produces the “whitest whites” in all water temperatures. The experiment was conducted in the following way. One hundred fifty white sheets were equally soiled. Thirty sheets were washed in each brand—l0 with cold water, 10 with warm water, and 10 with hot water. After washing, the “whiteness” scores for each sheet were measured with laser equipment.

Column 1: Water temperature code

Column 2: Scores for detergent 1 (first 10 rows = cold water, middle 10 rows = warm, and last 10 rows = hot)

Column 2: Scores for detergent 2 (same format as column 2)

Column 3: Scores for detergent 3 (same format as column 2)

Column 4: Scores for detergent 4 (same format as column 2)

Column 5: Scores for detergent 5 (same format as column 2)

a. What are the factors in this experiment?

b. What is the response variable?

c. Identify the levels of each factor.

d. Perform a statistic analysis using a 5% significance level to determine whether there is sufficient statistical evidence to infer that there are differences in whiteness scores between the five detergents, differences in whiteness scores between the three water temperatures, or interaction between detergents and temperatures.