I want to write a linear regression model with R programming for house price estimation with regressors room number, floor number, size etc. If you know good resources for model building in R like this one can you suggest me ? I want to know all of the stages of model building such as validation, non normality, non linearity etc. It is not neccessary to be linear regression actually but it is simple for first stage. How can I be sure that I did not forget something like checking conditions when I am building a model? I am very confused about model building in R. I looked websites but every website mention different things about building model. I need good and reliable source to depend my model on.Thank you