Section 9.2: Choosing Appropriate Tests
At the end of this section you should be able to answer the following questions:
- To what extent do nonparametric equivalents exist for common parametric tests?
- What factors are considered when you decide to use nonparametric statistics?
Multiple Considerations Required
When deciding to use nonparametric statistics, an examination of whether the mean or the median is the best representation of the center of the data distribution is needed. If it is found that the median is the best representation of the data’s center, then nonparametric tests are most likely to be appropriate, even with a larger sample of participants. If you have a small sample, then nonparametric statistics may be appropriate either way.
Each parametric test of difference we have discussed previously has a nonparametric equivalent, which can be used in cases where there is nonnormal data or a small sample size.
PowerPoint: Nonparametric Analogues
Please click on the link below to see slides with a chart of parametric tests with a nonparametric equivalent.