Re: st: stepwise et al

[Phil Schumm <pschumm@uchicago.edu>]

On Aug 27, 2007, at 10:52 AM, b.qureishi wrote:
> Instead a T statistic, I would get "." Does anyone know why this is  
> happening?

Presumably because Stata is unable to calculate the corresponding  
standard error(s) in this case.  This is often the result of some  
collinearity among your covariates, or some lack of variation in your  
outcome, or a mixture of both.  Also, pay attention to your  
estimation sample (i.e., the set of observations being used to  
estimate the model); often this gets reduced to a subset of the  
entire sample for some reason (e.g., missing data), and that's what  
leads to the problem.


-- Phil

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