Variable Selection

60

See 

Opening a data set

10.4

Working Environmental Data

This form allows the user to make a variety of changes to the raw

Sample/Environmental variables data prior to undertaking an analysis. Initially, the

user will be presented with a grid filled with the raw data; this can be adjusted using

the options in the panel below the data grid.

See 

Opening a data set

See the subjects below for further details of transformations etc

Data transformations

Relative adjustments

Dealing with zeros

Transposing data

10.5

Redundancy Analysis

Redundancy Analysis is an extension of multiple regression when there is more than

one response (species) variable. If there is only one species then RA reduces to a

simple multiple regression. It was first proposed by Rao (1964) but has been little

used by biologists. A good description of the procedure is to be found in

Legendre & Legendre (1998)

.

The input data comprises a biological data set of samples/species and another set of

environmental/explanatory variables. The results are normally presented as a biplot.

Working samples/species data

Sample/species data

Copyright 2004  PISCES Conservation Ltd