Hi,

I'm currently running regression models on cross-sectional data for which the outcome variables (I have two) are both clustered at zero. Of the 240 observations, around 100 are zero, while the others span from -60 to +40 for one dependent variable, and -2.5 to +2.5 (ordinal variable, iterations of 0.5) for the other dependent variable. Thus, the normality assumption is violated (as well as the homoskedasticity for one of the models). I will run both parametric tests (multiple regression) and nonparametric tests. To deal with the non-normality and heteroskedasticity, I've see suggestions to use vcs(robust) or vcs(bootstrap), or use rreg instead of reg. I'm not sure which to use, can anyone provide explanations of when to use which?

Thanks in advance,
Rens