mcChi {cocorresp} | R Documentation |
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
mcChi(Y, R0, eps = 1e-06)
Y |
a matrix for which standardised chi-square residuals are to be calculated. |
R0 |
row weights. |
eps |
tolerance - leave as default. |
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.
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) |
This function is not intended for casual use by users.
Gavin L. Simpson, based on Matlab code by C.J.F. ter Braak and A.P. Schaffers.
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