Question

Can someone please help me with this question on my psychology research methods review?

1. Mr. Loomis has been asked by Colgate to test market for new flavors of toothpaste: spare mint, chocolate mint, Peppermint comma and peanut butter. Mr. Loomis has decided to use a within-subjects design to test subjects.
   1. What is the primary advantage of using a within-subjects design for this study?
   2. What is the primary disadvantage of using a within-subjects design for this study?
   3. Is counterbalancing necessary in this study? Why?

Answer 1

a. Within- subjects design uses fewer participants for the research that can be as many as 30 participants for testing different conditions such as testing the market of four different flavours of Colgate. This method makes the research process effective by concentrating on the selected fewer participants with an aim to inverst heavily on finding the results.

b. Since within-subjects tests different conditions one after another there is a chance of having carryover effects. Carry-over effects happen when the result or finding of the first test adversely affect the other. Here in this research design, one result of the test of flavours of the Colgate might affect the other findings which might lead to fatigue and practice.

c. Counterbalancing might be necessary here since there can be effects of nuisance variables in the design. It happens when the few participants who are selected for the test are repeatedly subjected to the conditions of the test. As a result of the repeated test, the result might be skewed and therefore researcher needs to control the nuisance variables such as introducing the same flavour again and again.