Matlab scripts for 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:

  • Evaluate the Model I linear regressions using data from Bevington and Robinson (2003)
    • Examine the results for standard and weighted regressions.
    • Download the data files – Table 6.1 and Table 6.2ASCII text file format
  • Compare both linear regression models.
    • Download the data file. ASCII text file format
    • Examine the results from the various regression models.
    • View graphs of the regression models.
  • 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.
  • Bevington & Robinson (1992). Data Reduction and Error Analysis for the Physical Sciences, Second Edition, McGraw-Hill, Inc., New York.
  • Sokal and Rohlf (1995). Biometry, 3rd edition. W.H. Freeman and Company, San Francisco, CA.
  • Laws (1997). Mathematical Methods for Oceanographers. John Wiley and Sons, Inc., New York, NY.
  • Bevington & Robinson (2003). Data Reduction and Error Analysis for the Physical Sciences, Third Edition, McGraw-Hill, Inc., New York.


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Matlab scripts: Linear regressions
Introduction to Model I and Model II linear regressions
A brief history of Model II regression analysis
Index of downloadable files
Summary of modifications
Regression rules of thumb
Results for Model I and Model II regressions
Graphs of the Model I and Model II regressions
Which regression: Model I or Model II?
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