Question

Please note that for all problems in this course, the standard cut-off (alpha) for a test of significance will be .05, and you always report the exact power unless SPSS output states p=.000 (you’d report p<.001). Also, remember that we divide the p value in half when reporting one-tailed tests with 1 – 2 groups.

Problem Set 1: (14 pts) 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 (Ahn, Kim, & Aggarwal, 2013). They compared how people would respond to different poster campaigns. 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!”. All participants (N=7) viewed both posters on separate occasions (repeated measures design). After each session, participantes were asked to rate a series of items about how likely they would be to behave in an environmentally friendly manner. The Likert scale went from 1 (very unlikely) to 9 (very likely). Select and conduct the most appropriate statistical test based on the premise that all assumptions are met for a parametric test. Determine whether there is a difference in likelihood of turning off the light based on the poster campaign. Anthropomorphism Nonanthropomorphism 7.2 6.3 8.1 6.2 7.5 6.5 6.9 7.0 6.6 7.6 7.4 6.8 6.5 6.2

1. Paste appropriate SPSS output. (4 pts)

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

3. Write an APA-style Results section based on your analysis. All homework “Results sections” should follow the examples provided in the presentations and textbooks. They should include the statistical statement within a complete sentence that mentions the type of test conducted, whether the test was significant, and if relevant, effect size and/or post hoc analyses. Don’t forget to include a decision about the null hypothesis. (4 pts)

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

Answer 1

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 (Ahn, Kim, & Aggarwal, 2013). They compared how people would respond to different poster campaigns. 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!”. All participants (N=7) viewed both posters on separate occasions (repeated measures design). After each session, participantes were asked to rate a series of items about how likely they would be to behave in an environmentally friendly manner. The Likert scale went from 1 (very unlikely) to 9 (very likely).

SPSS output:

Paired Samples Statistics
		Mean	N	Std. Deviation	Std. Error Mean
Pair 1	Anthropomorphism	7.1714	7	.55891	.21125
	Nonanthropomorphism	6.6571	7	.51594	.19501

Paired Samples Test
		Paired Differences					t	df	Sig. (2-tailed)
		Mean	Std. Deviation	Std. Error Mean	95% Confidence Interval of the Difference
					Lower	Upper
Pair 1	Anthropomorphism - Nonanthropomorphism	.51429	.91548	.34602	-.33239	1.36096	1.486	6	.188

calculated t=1.486, P=0.188 which is > 0.05 level of significance. Ho is not rejected.

Effect size = (7.1714-6.6571)/0.91548 =0.56

Graph:

Result:

A paired-samples t-test was conducted to compare the behavior of the two conditions Anthropomorphism and Non Anthropomorphism. There was no significant difference in the ratings for Anthropomorphism (M=7.2, SD=0.56) and non Anthropomorphism (M=6.7, SD=0.52) conditions; t(6)=1.49, p = 0.188, effect size d=0.56.

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

If the assumptions had been violated, Wilcoxon signed rank test is the most appropriate statistical test.