On Mon, Dec 3, 2012 at 9:10 AM, Adel Enpaya <Adel.Enpaya@uws.ac.uk> wrote:
> HI guys
> When I run Tobit regression model , I have 138 observations and only 19 variables include 13 dummy variables. However, when I reduce the number of variables to 18, I get results, if 19 , no results obtained , can anyone tell me what is the problem and how to be sorted
> Ade
This is basically the same question you asked before. We gave you
answers. They all come down to the fact that you have insufficient
data to run simpler models like linear regression, to say nothing of a
complicated model like Tobit. A good rule of thumb is: 10-20 cases per
variable at minimum. You can get away with less when using simpler
models like OLS and need higher N when fitting a complicated model
like Tobit or ordinal probit. The models you want to run are well
below the recommendation for OLS.
Jay
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