A Company Has Tried to Improve the Effectiveness of Its

Multiple Choice

A company has tried to improve the effectiveness of its dishwashing detergent and wants to see if it works better than the original formula. They use 6 identical new dishwashers and load them identically with dirty dishes. Three packs of each of the two types of detergent are used, and they are randomly assigned to one of the six dishwashers. After the load is run, they rate each load for overall cleanliness. Which of the following is true?

A) Because each brand is used in three dishwashers, replication is used properly.
B) Blinding is impossible in this experiment because they must be able to see the dishes.
C) The explanatory variable is the different dishwashers.
D) A control group with no detergent at all is needed.
E) The response variable is the type of detergent.