Question

ONE SAMPLE T-TEST

Assignment 1: 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 0 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.

SCORES: -3, -3, -3, -3, -3, -3, -3, -3, -3,

-2, -2, -2, -2, -2, -2, -2, -2, -2,

2,

-1, -1, -1, -1, -1, -1, -1

0, 0, 0, 0, 0, 0, 0, 0, 0, 0

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)

Answer 1

From the given data, using calculator, the following statistics are calculated:

(i) n = Sample size = 36

(ii) = Sample mean = - 50/36 = - 1.3889

(iii) s = Sample standard deviation = 1.2935

(iv) SE = Estimated standard error = s/

                                                 = 1.2935/

                                                = 0.2156

(v) Mean difference = 1.3889

(vi)

t_obtained = 1.3899/0.2156

               = 6.4472

(vii)

Degrees of freedom (df) = n - 1 = 36 - 1 = 35

(viii)

= 0.05

Significance (2-tailed) = 2.0301

(ix)

Since calculated value of t is greater than critical value of t, the difference is significant. Reject null hypothesis.

Conclusion:
The data support the claim that the participants reported a significant change in mood at a .05 level of significance using a two ­tailed test.