From menstav@hotmail.com  Sat Sep  8 01:03:32 2001
From: menstav@hotmail.com (menstav@hotmail.com)
Date: Sat, 8 Sep 2001 02:03:32 +0200 (MET DST)
Subject: [Rd] anova in model simplification in glm (PR#1087)
Message-ID: <200109080003.CAA12990@pubhealth.ku.dk>

Full_Name: Menelaos Stavrinides
Version: 1.3. 1
OS: Windows 98
Submission from: (NULL) (193.129.76.90)


When model simplification is used in glm (binomial errors) and anova is used two
compare two competitive models one can use either an "F" or a "Chi" test.

R always performs an F test (Although when test="Chi" the test is labeled as
Chi, there isn't any difference between F and Chi test)

Let us assume model1 and model2, where model2 a simplified version of model1

model1_glm(y~factor1*factor2,binomial)
model2_update(model1,~.-factor2)
anova(model1,model2,test="F")# will give the same result as 
anova(model1,model2,test="Chi") 

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[Rd] anova in model simplification in glm (PR#1087)
menstav@hotmail.com