Question

Gouax (1971) hypothesized that we like others better when we’re in a good mood than when we’re in a bad mood.  He suggested that mood functions like a pair of sunglasses biasing our perceptions of others in the direction of our mood.  He tested his hypothesis by asking people who were either in a very positive mood or a very negative mood to rate how much they liked a young man described by a brief written profile.  Specifically, he approached people in a movie theater immediately after they had seen either a comedy (positive mood condition) or a tragedy (negative mood condition).  Supporting his hypothesis, people who had just watched the comedy reported liking the young man more than people who had just watched the tragedy.  

Although Gouax’s research is informative about the effects of mood upon liking for others, an important interpretive ambiguity still remains.  Because he did not include a neutral mood control condition, there are three possible explanations for his findings:  (1) positive mood increases liking for others in comparison to a neutral mood state, whereas a negative mood decreases liking relative to a neutral mood, (2) positive mood increases liking for others relative to a neutral or negative mood, and (3) negative mood decreases liking for others relative to a neutral or positive mood.

You have decided to conduct a study to more clearly test whether positive mood increases liking for others relative to neutral mood.   So, you induced in participants either a positive mood or a neutral mood by exposing them either to funny scenes from a comedy or neutral scenes from a neutral movie (one that was neither funny nor sad).

Next, you measured liking for the young man in Gouax’s profile by asking participants to respond to the following question:  (1) “How much do think you would like the young man?” Responses were made on 7-point scales with higher numbers indicating more positive responses.

1.  Statistical hypotheses:  State the null and alternative hypotheses.

2.  Perform a one-way ANOVA on the measure of liking for the young man.

3.  Based on the results of your ANOVA, should you reject or fail to reject the null hypothesis?  Explain.  On the basis of this decision, what conclusions do you make regarding the research hypothesis?  Present your conclusion as you would in a Results section of a research paper (use the in-class exercises we’ve completed as templates).

Condition:  

                         

1 = Positive mood

2 = Neutral mood

DM: “How much do think you would like the young man?” (1 = not at all, 7 = very much).                      

Data

ID        Condition       DM

1          1                      6

2          1                      5

3          1                      4

4          1                      5

5          1                      4          

6          1                      5          

7          1                      6          

8          1                      3

9          1                      4          

10        1                      5          

11        2                      2

12        2                      2

13        2                      3

14        2                      4

15        2                      3

16        2                      5

17        2                      2          

18        2                      3

19        2                      2

20        2                      2

Answer 1

1)

ANOVA

Ho: µ1 = µ2

Ha: at least one mean is different

2)

Using minitab

stat -> anova

F = 18.36, p-value = 0.000 < alpha

hence we reject the null hypothesis

we conclude that there is evidence that means are different