R equivalent of SAS Cochran-Mantel-Haenszel tests?
Dear Michael, It sounds as a linear-by-linear loglinear model (and its variants) which uses scores for one or more variables in the table.. (see Agresti, 1990, Categorical Data Analysis. I do remember the pages and I have not the book here..) If this is the case, you can use standard call to glm(.., family=poisson) with score variables in the linear predictor. For instance for a two-way table with ordered variables the linear-by-linear model is, glm(freq~factor(x)+factor(y)+I(score.x*score.y), family=poisson) The CMH test, probably, is the score test of the parameter of I(score.x*score.y).. best, vito Michael Friendly ha scritto:
In SAS, for a two-way (or 3-way, stratified) table, the CMH option in
SAS PROC FREQ gives
3 tests that take ordinality of the factors into account, for both
variables, just the column variable
or neither. Is there an equivalent in R?
The mantelhaen.test in stats gives something quite different (a test of
conditional independence for
*nominal* factors in a 3-way table).
e.g. I'd like to reproduce:
*-- CMH tests;
proc freq data=sexfun order=data;
weight count;
tables husband * wife / cmh chisq nocol norow;
run;
The FREQ Procedure
Summary Statistics for Husband by Wife
Cochran-Mantel-Haenszel Statistics (Based on Table Scores)
Statistic Alternative Hypothesis DF Value Prob
1 Nonzero Correlation 1 10.0142 0.0016
2 Row Mean Scores Differ 3 12.5681 0.0057
3 General Association 9 16.7689 0.0525
==================================== Vito M.R. Muggeo Dip.to Sc Statist e Matem `Vianelli' Universit? di Palermo viale delle Scienze, edificio 13 90128 Palermo - ITALY tel: 091 6626240 fax: 091 485726/485612 http://dssm.unipa.it/vmuggeo