How it is done: Using MATLAB®

## Model I and Model II Regressions

- A basic introduction to Model I and Model II linear regressions:
- what they are,
- how they are different,
- why they are different,
- and when to use them.
- A brief history of Model II regressions.
- Who led the intellectual development of these regression techniques.
- Plus, a list of their seminal papers.
- An index of downloadable files for use with MATLAB®.
- Model I regressions: normal (Y-on-X), reversed (X-on-Y) and weighted (wY-on-X).
- Model II regressions: major axis, geometric mean and least-squares-cubic.
- Summary of modifications made to these files.
- Some rules of thumb to help decide which model regression to use:
- When to use Model I vs Model II.
- Within each type, which of the various models to use.
- Testing Model I and Model II regressions:
- Here's a way to test and compare your linear regression routine against mine.
- Download the data file.
*ASCII text file format* - Examine the results from the various regression models.
- View graphs of the various regression models in gif or postscript format.
- How to know which regression you are using.
- For further reading regarding Model I and II regressions, see:
- Ricker (1973). Linear regressions in Fishery Research.
*J. Fish. Res. Board Can.*30: 409-434. - Laws and Archie (1981). Appropriate use of regression analysis in marine biology.
*Marine Biology*65: 13-16. - Sokal and Rohlf (1995).
**Biometry,**. W.H. Freeman and Company, San Francisco, CA.*3rd edition* - Laws (1997).
**Mathematical Methods for Oceanographers**. John Wiley and Sons, Inc., New York, NY.