A researcher for a cereal company wants to know how advertisements affect the consumer's view of her product. in her study, she wants to have one group of participants watch two separate commercials a

A researcher for a cereal company wants to know how advertisements affect the consumer's view of her product. in her study, she wants to have one group of participants watch two separate commercials and then rate how likely they are to purchase the cereal in the future. one commercial is "happy" and attempts to put customers in a good mood; the other commercial is "healthy" and focuses on the health benefits of the cereal. the researcher is worried that consumers will rate the cereal differently the second time just because they have rated the cereal before. in order to control for this undesirable effect, she has half of the participants watch the "happy" commercial first, while the other half of the participants watch the "healthy" commercial first.