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Chapter 7 - Analysing the Data Part IV - Analysis of Variance Chapter 1 - Behavioural Science and research Chapter 2 - Research Design Chapter 3 - Collecting the Data Chapter 4 - Analysing the Data Part I - Descriptive Statistics Chapter 5 - Analysing the Data Part II - Inferential Statistics Chapter 6 - Analysing the Data Part III - Common Statistical Tests

 

Chapter 7: Analysing the Data
Part IV : Analysis of Variance

 

Scenario and Data Set #5
Report

Task 1.

   

Testing conditions

 

 
 

 

Small room

Large room

Lecture conditions

Small room

18.0 (2.92)

4.0 (2.74)

11.0

Combined means for Lecture conditions

Large room

4.0 (3.0)

16.0 (3.39)

10.0

 

 

11.0

10.0

 
    Combined means for
testing conditions
   

 

Task 2.

The Summary Table

SOURCE

SS

DF

MS

F

Sig of F

Lecroom

5.0

1

5.0

.55

.470

Testroom

5.0

1

5.0

.55

.470

Lecroom X

845.0

1

845.0

92.60

.000

Testroom - Error

146.0

16

9.13

Total

1001.0

19

52.68

 

Task 3.

The homogeneity of variance tests indicate that this assumption was not violated.

 

Task 4.

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.

HSD

= 4.05 * SQRT(9.13/5)

 

= 4.05 * 1.351

 

= 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.

Matrix of ordered means

 

LlecStest
4.0

SlecLtest
4.0

LlecLtest
16.0

SlecStest
18.0

LlecStest
4.0

-

0.0

12.0*

14.0*

SlecLtest
4.0

-

12.0*

14.0*

LlecLtest
16.0

-

2.0

SlecStest
18.0

-

 

Task 5. Graph of interaction

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.

Task 6. Interpretation

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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