ONE SAMPLE T-TEST
Change in Mood Following a Romantic Movie Clip
A researcher asks participants to watch a short romantic movie clip. The movie clip depicts a romantic scene ending with two long-lost lovers embracing in a kiss. After the short romantic movie clip, participants are asked to indicate how the romantic movie clip has affected their mood on a bipolar scale ranging from -3 (much worse mood) to +3 (much better mood), with 0 indicating no change in mood. The results are given below. It was assumed that the average participant would give a rating of O if there were no change in mood. Test whether or not participants reported a significant change in mood at a .05 level of significance using a twotailed test.
With regard to the SPSS exercise, answer the following questions:
Based on the SPSS output, state the following values:
Sample size ______________________________
Sample mean ______________________________
Sample standard deviation ______________________________
Estimated standard error ______________________________
Based on the table shown in SPSS, state the following values associated with the test statistic:
Mean difference ______________________________
t obtained (t) ______________________________
Degrees of freedom (df) ______________________________
Significance (2-tailed) ______________________________
Based on the value of the test statistic, what is the decision for a one-sample t test? (Circle one)
Retain the null hypothesis Reject the null hypothesis
Compute Cohen's d and state the size of the effect as small, medium, or large. (Show your work.) In a sentence, also state the number of standard deviations that scores have shifted in the population. Note: The tables in SPSS give you all the data you need to compute effect size.
Compute proportion of variance using eta-squared or omega-squared, and state the size of the effect as small, medium, or large. (Show your work.) In a sentence, also state the proportion of variance in the dependent variable that can be explained by the factor. The tables in SPSS give you all the information you need to compute proportion of variance.
State the final report.