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for ''lm'' and the ''Anova()'' procedure for ''lmer'' in R. the Anova () procedure is available by downloading the ''car'' extension package from [http://cran.r-project.org/ here.] |
for ''lm'' and the ''Anova()'' procedure for ''lmer'' in R. the Anova () procedure is available by downloading the ''car'' extension package from [http://cran.r-project.org/ here.] |
Sums of Squares used by R in lm, aov and lmer
R calculates sequential or Type I SS by default when using lm, lmer and aov as opposed to the type III SS (default in SPSS) which partials out effects of other terms in the model. A hierarchical approach is suggested which gives the same results for both sums of squares and only looks at the highest order terms in a model. See [http://tolstoy.newcastle.edu.au/R/help/05/04/2981.html here].
Type III SS [http://tolstoy.newcastle.edu.au/R/help/05/08/9560.html may be obtained] using terms of form
fit <- anova(lm(y~x+z)) anova(fit, ssType=3)
for lm and the Anova() procedure for lmer in R. the Anova () procedure is available by downloading the car extension package from [http://cran.r-project.org/ here.]