The three factors
There are three factors when deciding on a test:
- Test of difference or a correlation
- Experimental design
- Levels of management.
Difference of correlation
Correlation: A relationship between variables.
Usually a research experiment, with two or more groups & you are looking for a change in the DV based IV, eg. the difference between men and women finding reality TV interesting.
Independent group design (unrelated data) - different participants in each condition.
Repeated measures design (related data) - each participant tested in all conditions.
Matched pairs design (related data) - participants matched on characteristics important for the study.
Levels of management
Nominal - catagories/ groups
Ordinal - measurements relate to variable, measurements can be placed in ascending or descending order.
Interval - measured in units of equal measurement, eg. height in cm.