1. On your white boards…
Write an example of Nominal data… Write an example of Ordinal data… Write an example of Interval/ratio data…

2. Types of Data: This dictates which test you use…
Nominal Data:
Used for exclusive groups or categories e.g. Male or female, Psychology graduate or Sociology Graduate.
Then frequencies are recorded for each group.
Ordinal Data:
Order of things e.g. Medallists at the Olympics, Horses in a race
We do not measure the gaps/intervals, (BUT note: they maybe different sizes)
Interval or Ratio Data:
Measure on a scale e.g. temperature, distance
The gaps/intervals are equal

3. Which statistical test do we use to find our observed value?
Decision 1: What are you looking for?
Differences
Correlation
Decision 2: What level of measurement?
Spearman’s rho
Nominal
Ordinal and Interval/Ratio
Chi squared test
Decision 3: What experimental design
Independent groups
Repeated measures/ or matched
Mann Whitney U test
Wilcoxon matched pairs rank test

4. Measuring a difference and have nominal data I would use…
If I am…
Measuring a difference and have nominal data I would use…

5. Chi Squared

6. If I am…
Measuring a difference and have interval/ratio data and I have independent groups I would use…

7. Mann-Whitney U

8. If I am…
Measuring a difference and have interval/ratio data and I have repeated measures or matched pairs I would use…

9. Wilcoxon

10. If I am…
Measuring a correlation and have ordinal or interval/ratio data I would use…

11. Spearman’s Rho

12. For 2 marks each…
Why has the psychologist chosen to use a Mann Whitney U test
Why has the psychologist chosen to use a Spearman’s rho
Why has the psychologist chosen to use a Chi squared test
Why has the psychologist chosen to use a Wilcoxon matched pairs rank test
The Psychologist use a Spearman’s Rho because…

13. Reading the Tables…
Higher or Lower??

14. On the Stats Sheet
Highlight: What type of data do they test Does the observed value have to be LESS than or GREATER than the critical value

15. Higher or Lower…
Chi Squared

16. Higher or Lower…
Higher

17. Higher or Lower…
Mann U Whitney

18. Higher or Lower…
Lower

19. Higher or Lower…
Wilcoxon

20. Higher or Lower…
Lower

21. Higher or Lower…
Spearman’s Rho

22. Higher or Lower…
Higher

23. Higher or Lower… Whichever way you are looking; Higher or Lower
It will always mean the results are significant (or not)
P ≤ 0.05 You must ALWAYS write it like this!

24. Exam Q booklets – Find them!
Find every question that refers to significance, statistical tests, type 1 & 2 errors

25. Finish Jan , 22, 23
January 2012
21, 22, 23, 24