1. Which type of inferential test should be used?

2. What is the criteria that it depends on?
whether the researcher is testing for differences between groups (experiment) or a correlation between two co- variables.
Level of measurement (nominal, ordinal interval)
Experimental design (independent groups, matched pairs, repeated measures)

3. Can you remember the 7 statistical tests?
The seven tests that you can be asked about (but won’t have to calculate) in the exam: Chi-squared (χ2) Wilcoxon T Mann-Whitney U Spearman’s Rho Unrelated t-test Related t-test Pearson’s r How do you know which test to use? You need to learn the following criteria, but there is no need for you to understand why this is the case

4. LOOKING FOR A CORRELATION REPEATED MEASURES DESIGN
What test to use?
Looking for a difference
LOOKING FOR A CORRELATION
DATA LEVEL
INDEPENDENT
GROUPS DESIGN
REPEATED MEASURES DESIGN
NOMINAL
Chi-square
Sign Test
Chi square
ORDINAL
Mann-Whitney U test
Wilcoxon test
Spearman’s
rho
INTERVAL OR RATIO
Unrelated t test
Related t test
Pearsons r

5. Test of difference or correlation
At Interval level
At Interval level
Nominal or at least ordinal level data?
At ordinal level
Pearson’s r
Repeated measures
Independent groups design
Spearman’s Rho
Related t test
Chi square
Chi can also be association.
Correlation between chewing gum and having nice breadth.
independent groups design?
Repeated measures/matched pairs or independent groups design?
Mann-Whitney U Test
Wilcoxon T
Related t test

6. Chi-Squared
Chi-Squared = nominal data = independent groups design

7. Independent groups Design
Mann-Whitney U Test-
Independent women
Rank first in the charts
Independent groups Design
Ordinal data

8. Wilcoxon T Test
Wilcoxon T Test Repeated measures- At least ordinal (1st in the race)
Cok sits at the front. Repeating movement. Want to come first.

9. Spearmans Rho
There is a correlation between spearmints chewing gum and fresh breath

10. Unrelated t-test
When you are single, you are independent and Unrelated to a partner, so you have an interval from household chores

11. Related t-test
Back with your partner…. The interval is over… Being related to someone else means…. Repeatedly having to do the household chores

12. Pearson’s r
Brighton Pear is correlational to the west pier. The interval between is made up of a pebbly beach and too many tourists in the summer.

13. Test of difference or correlation
At Interval level
At Interval level
Nominal or at least ordinal level data?
At ordinal level
Pearson’s r
Repeated measures
Independent groups design
Spearman’s Rho
Related t test
Chi square
Chi can also be association.
Correlation between chewing gum and having nice breadth.
independent groups design?
Repeated measures/matched pairs or independent groups design?
Mann-Whitney U Test
Wilcoxon T
Related t test

14. Which test to choose. Activity
Have a go at trying to draw the diagram yourself on mini whiteboard.

15. See handout… What test to use? Looking for a difference
Looking for a correlation
Independent
groups design
Nominal
Not possible
Interval or Ratio
Unrelated t test
Pearsons r

16. LOOKING FOR A CORRELATION REPEATED MEASURES DESIGN
What test to use?
Looking for a difference
LOOKING FOR A CORRELATION
DATA LEVEL
INDEPENDENT
GROUPS DESIGN
REPEATED MEASURES DESIGN
NOMINAL
Chi-square
Sign Test
Chi square
ORDINAL
Mann-Whitney U test
Wilcoxon test
Spearman’s
rho
INTERVAL OR RATIO
Unrelated t test
Related t test
Pearsons r

17. Now you need to justify each test
Fill in the gaps
The Spearman’s Rho was used because the data can be treated as at least 1)_______________ and the researchers were studying a possible 2)_________________ between two co-variables
1 = Ordinal 2 = Correlation (or relationship)

18. Now you need to justify each test
Fill in the gaps
The Chi-Square test was used because the data can be treated as 1)_______________ and the researches had hypothesised that there will be 2)___________________ between conditions when using the 3) _________________________ design.
1 = Nominal 2 = a difference 3 = Independent groups
(please note that the Chi-square is also used as a test of association)

19. Now you need to justify each test
Fill in the gaps
The Wilcoxon T test was used because the data can be treated as 1)_______________ and the researches had hypothesised that there will be 2)___________________ between conditions when using the 3) _________________________ design.
1 = ordinal 2 = a difference 3 = Repeated Measures (please note that the Wilcoxon T is also used for a matched-pairs design)

20. Now you need to justify each test
Fill in the gaps
The Mann-Whitney U test was used because the data can be treated as 1)_______________ and the researches had hypothesised that there will be 2)___________________ between conditions when using the 3) _________________________ design.
1 = ordinal 2 = a difference 3 = independent groups

21. Test your understanding!
Using your newly found knowledge identify the test that would be suitable for the following:
An experiment with nominal data and an independent groups design
Ordinal data on both measures in a study to see if two measures are associated
An experiment with and independent groups design in which the DV is measured on a ordinal scale
A study using a correlational technique in which one measure is interval and the other is ratio.
An experiment in which all participants were tested with alcohol and without alcohol on a memory test
An experiment in which reaction time was tested using an independent subject design

22. ANSWERS
An experiment with nominal data and an independent groups design
chi-squared test
Ordinal data on both measures in a study to see if two measures are associated
Spearman’s rank correlation / Rho
An experiment with and independent groups design in which the DV is measured on a Ordinal scale
Mann-Whitney U test
A study using a correlation technique in which one measure is interval and the other is ratio
Pearsons r
An experiment in which all participants were tested with alcohol and without alcohol on a memory test
Wilcoxon’s T test
An experiment in which reaction time was tested using an independent subject design
Unrelated T-Test

23. Which test to choose. Activity
Complete the exam questions on your hand out.