|
Size: 1092
Comment:
|
← Revision 6 as of 2013-03-08 10:17:44 ⇥
Size: 1092
Comment: converted to 1.6 markup
|
| Deletions are marked like this. | Additions are marked like this. |
| Line 21: | Line 21: |
| [wiki:FAQ Return to Statistics FAQ page] | [[FAQ|Return to Statistics FAQ page]] |
| Line 23: | Line 23: |
| [wiki:CbuStatistics Return to Statistics main page] | [[CbuStatistics|Return to Statistics main page]] |
| Line 25: | Line 25: |
| [http://www.mrc-cbu.cam.ac.uk/ Return to CBU main page] | [[http://www.mrc-cbu.cam.ac.uk/|Return to CBU main page]] |
| Line 27: | Line 27: |
| These pages are maintained by [mailto:ian.nimmo-smith@mrc-cbu.cam.ac.uk Ian Nimmo-Smith] and [mailto:peter.watson@mrc-cbu.cam.ac.uk Peter Watson] | These pages are maintained by [[mailto:ian.nimmo-smith@mrc-cbu.cam.ac.uk|Ian Nimmo-Smith]] and [[mailto:peter.watson@mrc-cbu.cam.ac.uk|Peter Watson]] |
Residuals and Non-normality
This page will give some tips on aspects of looking at residuals in order to assess non-normality. In particular it will stress how
- in repeated measures data, the thing that matters is the distributions of differences between pairs of measures (or more general contrasts in the repeated measures).
- in grouped data, it is the residuals adjusted for group means that matter
Consider this very small example:
X1 |
X2 |
1 |
2 |
2 |
1 |
3 |
2 |
1001 |
1002 |
The distributions of the variables are very skewed. The distribution of the differences (for a repeated measures t-test) are at least symmetrical, if not normal. [Last updated on 21 September, 2010]
Return to Statistics main page
These pages are maintained by Ian Nimmo-Smith and Peter Watson