Dear all,
  I have two questions about data normality.
  I used stepwise multiple regression to determine which variables contributed to tree growth, and want to built a model to explain tree growth. Sample size is about 50 tree species, I think it is not a large sample size, and some variables are not normal distribution.
1. Do I have to transform them to normal distributions before I perform multiple regression?
2. Two variables can not transform to normal distributions although I used some methods (e.g log, sqrt, boxcoxfit), what should I do for the two variables?
Thank you and best wishes!
                                                                                                                     Yong Shen                                           
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