Simple introduction to linear models in R It was hard for me to understand linear models in R. There are a lot of documents for the case, but many of them are technical manuals rather than teaching the concept.
I found this article really simple and instructive, I hope it would be useful for the other people who have the same problem. 
Do you have any better suggestion?
 A: I've spent a lot of time looking through R manuals. The best one that I've seen is Grant Farnsworth's "Econometrics in R". Check it out: http://cran.r-project.org/doc/contrib/Farnsworth-EconometricsInR.pdf. It's concise, but quickly covers a broad range of topics. The article you found looks good too!
A: *

*Hamilton, "Low-Tech Causal Modeling", 2008

*Diez et al., "Introduction to linear regression" ch. 11 in OpenIntro Stats,  2nd ed., 2012

*Gelman and Hill, ch. 3-4 in Data Analysis Using Regression and Multilevel/Hierarchical Models, 2007

*McIntosh, “Doing” Applied Econometrics”, c. 2010


That's probably a bit more than a hundred pages, with roughly half the content from Gelman and Hill, who use R. I realize the book is not free, though.
A: Here is another resource.  http://cran.r-project.org/doc/contrib/Faraway-PRA.pdf It is targeted at the fundamentals of using R for Regression and ANOVA.  Both single variable regression, multivariate regression, single factor and multifactor ANOVA are discussed.   This was the last version 2002 before the author published a book with this as a subset "Linear Models with R" (very good, by the way IMO)
