mcChi {cocorresp} R Documentation

## Standardised chi-square residuals

### Description

Scales a matrix, Y, to its standardised chi-square residuals (o - e) / \sqrt{e} (if R_0 = R, where R contains the row sums of matrix Y) so that further analysis can be unweighted

### Usage

mcChi(Y, R0, eps = 1e-06)


### Arguments

 Y a matrix for which standardised chi-square residuals are to be calculated. R0 row weights. eps tolerance - leave as default.

### Details

This function implements equation 8 of ter Braak and Schaffers (2004) by firstly applying equation 7 to form matrix Q using row and column sums of Y as weights, and, secondly, by applying equation 8 to form a matrix of standardised chi-square residuals from Q by pre-multiplication of Q by \sqrt{R_0} and post-multiplication of Q by \sqrt{K}, where K is the column sums of Y.

### Value

A list with the following components:

 Ychi  the matrix of standardised chi-squared residuals of Y Kn  the column sums (K) of Y divided by sum(K)

### Note

This function is not intended for casual use by users.

### Author(s)

Gavin L. Simpson, based on Matlab code by C.J.F. ter Braak and A.P. Schaffers.

### References

Ter Braak, C.J.F and Schaffers, A.P. (2004) Co-Correspondence Analysis: a new ordination method to relate two community compositions. Ecology 85(3), 834–846

[Package cocorresp version 0.4-3 Index]