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Chapter 7: Analysing the Data |
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Scenario and Data Set #5
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Testing conditions |
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Small room |
Large room |
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| Lecture conditions |
Small room |
18.0 (2.92) |
4.0 (2.74) |
11.0 |
Combined means for Lecture conditions |
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Large room |
4.0 (3.0) |
16.0 (3.39) |
10.0 |
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11.0 |
10.0 |
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| Combined means for testing conditions |
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SOURCE |
SS |
DF |
MS |
F |
Sig of F |
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Lecroom |
5.0 |
1 |
5.0 |
.55 |
.470 |
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Testroom |
5.0 |
1 |
5.0 |
.55 |
.470 |
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Lecroom X |
845.0 |
1 |
845.0 |
92.60 |
.000 |
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Testroom - Error |
146.0 |
16 |
9.13 |
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Total |
1001.0 |
19 |
52.68 |
The homogeneity of variance tests indicate that this assumption was not violated.
The only significant effect was the interaction. Tukey's HSD test on this interaction (i.e., the four cell means) follows.
Here there are 4 means being compared and the DF for the error term is 16. Howell, q = 4.05. Each cell mean is based on 5 observations, so N = 5.
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HSD |
= 4.05 * SQRT(9.13/5) |
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= 4.05 * 1.351 |
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= 5.47 |
All pairs of cell means that are greater than or equal to 5.47 apart are significantly different. It is easily seen from the table in Answer 1 that the two smallest means are not significantly different from each other and that the two largest means are not significantly different from each other. However, the two largest means are clearly significantly different to the two smallest means. It is hardly necessary to construct a matrix of ordered means, but for the exercise, it is shown below.
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LlecStest |
SlecLtest |
LlecLtest |
SlecStest |
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LlecStest |
- |
0.0 |
12.0* |
14.0* |
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SlecLtest |
- |
12.0* |
14.0* |
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LlecLtest |
- |
2.0 |
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SlecStest |
- |
The plot of the cell means is shown in the previous figures 7.14 and 7.15 and clearly indicates a significant interaction with no main effects. The number of correct responses in the test depended on both the room the information was delivered and the room in which the testing occurred. The lowest number of correct responses occurred when the testing was in a room different to the one in which the material was learnt. Conversely, the greatest number correct occurred when the testing was in the same size room as where the material was learnt.
Note that this graph is still rather cludgy. It would not be good enough for a publication, but it is about the best I could do from SPSS. This data was obviously set up to show a remarkable interaction with no main effects.
The most useful interpretation again focuses on the interaction.
The experiment showed that students showed significantly greater recall (F(1,16) = 92.6, p < .001) of unfamiliar material when tested in the same room as that in which the material was presented. This suggests that conditioned place learning has taken place such that the environmental cues associated with the acquisition of the material to be learned aided in the recall of that material one week later. The association between the environmental cues and the acquisition and recall of material was most likely inadvertent or non-conscious although this remains to be examined experimentally.
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