1. 4. Data Interpretation
Drawing Conclusions

2. Instructions
Look at the results from the following five investigations and draw conclusions.
Comment on whether or not the result is significant and the strength of the effect. You will need to use critical value tables to do this. Use the 5% significance level throughout.
If measures of central tendency and dispersion are quoted, comment on them and also any anomalous results.

3. Chi-Square Piaget Conservation Experiment
Hypothesis: -Seven year olds will be more likely to be able to conserve volume than five year olds.
See the next slide for contingency table of raw data.
After calculation X2 = 8.64, df = 1, p < 5%

4. Chi-Square (Continued)
Number able to conserve
Number unable to conserve
Row total (RT)
5 year olds 20
7 year olds
Column Totals (CT) 25 15
Grand Total (GT) = 40

5. Mann Whitney U Test
Hypothesis: - Males will score higher on an aggression questionnaire than females.
After Calculation U = 47, N1 = 10, N2 = 10
Males
Females
 Scores on questionnaires 16 14 11 12 4 6 15 9 20 5 13
11.8
Mean
4.54
3.86
Standard Deviation

6. Wilcoxon Test
Top Half of Face 10
Bottom Half of Face
Number of faces identified correctly 8 11 4 9 5
8.36
8.54
Mean
2.27
2.65
Standard Deviation
Hypothesis: - Participants will be more likely to identify a celebrity from the top half of their face rather than the bottom.
After Calculation W = 17.5, N = 10.

7. Sign Test
Participant No:
Attitude before film
Attitude after film
Direction of Influence 1
For
Against - 2 3 4
No change 5 6 7 8 9 10 +
A study was conducted to discover if students changed their attitude towards the death penalty after watching ‘The Green Mile’.
 Experimental Hypothesis: - Watching the film ‘The Green Mile’ will influence student’s attitudes to the death penalty. (non-directional – two-tailed)
After calculation S = 1, N = 9 (no change omitted)

8. Spearman’s Rank Order Correlation Co-efficient
Murstein’s Matching Hypothesis of Interpersonal Attraction.
Hypothesis: - There will be a positive correlation between attractiveness ratings given to brides and grooms
After Calculation rs = 0.689, N = 10.
Grooms – Average Ratings
Brides – Average Ratings 2
2.5
3.6
6.4
6.5
5.2
5.8
7.3
4.2
5.5
4.5
5.4
4.1
5.3
4.9
6.3
2.8
2.6
Again, worth a summary of key learning points on a last slide?

9. Calculating Statistics
A variety of statistics calculators are available free online, or can be downloaded free from the web. Here are just a few; if you search using an online search engine, we are sure you’ll find more!