Use the following to answer questions
Scenario I
Scenario I is based on and presents fabricated data consistent with the following study:
Merikle,P.M. ,& Skanes,H.E.(1992).Subliminal self-help audiotapes: A search for placebo effects.Journal of Applied Psychology,77(5),772-776.doi:10.1037/0021-9010.77.5.772
Merikle and Skanes (1992)investigated the effectiveness of subliminal self-help audiotapes to promote weight loss in overweight females seeking to lose weight.Participants were randomly assigned to groups.Participants in two groups were instructed to listen to audiotapes containing subliminal messages associated with weight loss daily.Group 1 (the subliminal group)actually received these tapes.Group 2 (the placebo group)received tapes containing subliminal messages associated with relieving dental anxiety.Finally,a third group of participants was not given audiotapes and was told that they were on a waiting list to participate in the study.All participants-including the participants on the waiting list-were weighed weekly for 5 weeks.The average total weight loss (and standard deviations)for the three groups after the fifth week is presented in Figure 5.1.
Figure 5.1
-(Scenario I)Suppose that a company markets a subliminal audiotape designed for people wanting to lose weight.As evidence that the product is effective,it cites a study based on 500 randomly selected overweight participants demonstrating that people listening to the tapes for 10 weeks lost-on average-6 pounds.Which statement is NOT a reason to be skeptical of these claims?
A)The weight loss could have been due to a placebo effect.
B)The weight loss probably is not representative of how much weight a typical overweight person would lose.
C)The weight loss could be due simply to the fact that the participants were motivated to lose weight.
D)It is impossible to determine if the weight loss was caused by the subliminal messages based on the information provided.

Question

Use the following to answer questions 
Scenario I
Scenario I is based on and presents fabricated data consistent with the following study:
Merikle,P.M. ,& Skanes,H.E.(1992).Subliminal self-help audiotapes: A search for placebo effects.Journal of Applied Psychology,77(5),772-776.doi:10.1037/0021-9010.77.5.772
Merikle and Skanes (1992)investigated the effectiveness of subliminal self-help audiotapes to promote weight loss in overweight females seeking to lose weight.Participants were randomly assigned to groups.Participants in two groups were instructed to listen to audiotapes containing subliminal messages associated with weight loss daily.Group 1 (the subliminal group)actually received these tapes.Group 2 (the placebo group)received tapes containing subliminal messages associated with relieving dental anxiety.Finally,a third group of participants was not given audiotapes and was told that they were on a waiting list to participate in the study.All participants-including the participants on the waiting list-were weighed weekly for 5 weeks.The average total weight loss (and standard deviations)for the three groups after the fifth week is presented in Figure 5.1.
Figure 5.1 
-(Scenario I)Suppose that a company markets a subliminal audiotape designed for people wanting to lose weight.As evidence that the product is effective,it cites a study based on 500 randomly selected overweight participants demonstrating that people listening to the tapes for 10 weeks lost-on average-6 pounds.Which statement is NOT a reason to be skeptical of these claims?
A)The weight loss could have been due to a placebo effect. 
B)The weight loss probably is not representative of how much weight a typical overweight person would lose. 
C)The weight loss could be due simply to the fact that the participants were motivated to lose weight. 
D)It is impossible to determine if the weight loss was caused by the subliminal messages based on the information provided.

Quizplus · Accepted Answer

The fact that the study cited by the company was based on 500 randomly selected overweight participants is a good indication that the results are statistically significant and not due to chance. The other statements are all potential reasons to be skeptical of the claims made by the company. A is a potential confounding factor, C is a potential alternative explanation, and D highlights a limitation in the design of the study. However, B is not a reason to be skeptical because there is no information provided about how much weight a typical overweight person could expect to lose in 10 weeks.

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