Question

Research Scenario: The following scenario is based loosely on an actual study conducted in 2013 by Ahn, Kim, and Aggarwal– please note that methods and data have been modified for educational purposes.

Do you turn off the light when you leave the room? South Korean researchers wondered how they could increase the number of people who do by use of posters (Ahn, Kim, & Aggarwal, 2013). In one, an image of a light bulb was anthropomorphized by giving it eyes, nose, and a mouth, as well as adding the words, “I’m burning hot, turn me off when you leave!”. In a second, there were no human features on the light bulb and the text simply said, “Our bulbs are burning hot, turn the lights off when you leave!”.

They compared how people would respond to the two posters by having each displayed in separate coffee rooms for two weeks. Although the coffee rooms were different, they were matched as closely as possible on as many parameters as possible (similar business, # of employees, et cet) such that this is a correlated groups design. Percent likelihood of someone turning off the light upon exiting was calculated every day and is presented below. Select and conduct the most appropriate statistical test based on the premise that all assumptions are met for a parametric test and this is a correlated groups design. Determine whether there is a difference in likelihood of turning off the light based on the poster campaign.

Anthropomorphism	Nonanthropomorphism
87.2	76.3
78.1	86.2
77.5	76.5
91.9	87.0
86.6	77.6
87.4	86.8
76.5	76.2
65.7	65.2
88.3	55.4
57.5	51.7
68.6	61.8
67.9	53.7
73.5	62.9
77.7	57.6

1. Paste appropriate SPSS output. (3 pts)

2. Paste the appropriate SPSS graph. (3 pts)

3. Calculate the effect size. Show all of your work. Is it considered “small”, “medium”, or “large”? (3 pts)

4. Write an APA-style Results section based on your analysis. All homework “Results sections” should follow the examples provided in the presentations and textbooks for that particular statistical test. Don’t forget to include a decision about the null hypothesis. (3 pts)

5. If the assumptions had been violated, what would the most appropriate statistical test be? (3 pts)

Answer 1

100.00 90.00- I 80.00 Turning_off 70.00 60.00 50.00 Anthropo Nonanthr Group

From the above box-plot, most of the data are overlap. Hence, we can conclude that the means likelihood of turning off the light base between the two groups may not be different.

Group Statistics Std. Error N Mean Mean Groun Turning_off Anthropomorphism Nonanthropomorphism 14 14 77.4571 69.6357 Std. Deviation 10.10291 12.76459 2.70012 3.41148 Independent Samples Test Levene's Test for Equality of Variances t-test for Equality of Means 95% Confidence Interval of the Difference F t Sig. .110 df 26 Sig. (2-tailed) .084 Mean Difference 7.82143 Std. Error Difference 4.35073 Lower -1.12162 Upper 16.76448 Turning_off 2.734 1.798 Equal variances assumed Equal variances not assumed 1.798 24.697 .084 7.82143 4.35073 -1.14464 16.78749

The P-value for the F-test to compare the variances of the two gropus is 0.110. Hence, we can conclude that the variances of the two groups are the same. Thererfore, we should use the 2 sample t-test with the assumption of equal varices. THe t-value under the equal variances assumption is 1.798 and coreesponding p-value for the test is 0.084. This p-value is greater than 0.05 significane level. Hence, we can conclude that there is no evidence to say that there is a difference in likelihood of turning off the light based on the poster campaign.

Effect size=t*sqrt(1/n1+1/n2)=1.798*sqrt(1/14+1/14)=0.6796.

Interpretation of effect size= The effect size=0.6796 indicates the two groups differ by 0.6796 standard deviation. Also, the estimated effect size is less than 0.8 and greater than 0.6. Hence, this effect size is medium.

If the assumptions had been violated, the most appropriate statistical test would be Mann-Whitney Test.