Re: st: return of p-value for beta after regress command

[Richard Williams <Richard.A.Williams.5@ND.edu>]

At 04:10 PM 1/1/2006, Colin Cooke wrote:
> I am interested in looking at the p-value for each beta after running
> a series of regression commands.  I have a program that performs
> regression after each "leave one out" iteration in order to determine
> how infuential outliers effect the beta coefficients and p-values for
> my model.  Unfortunately, I am unable to determine how to get stata to
> return the p-value for each beta coefficient after a -regress-
> command.  -ereturn list- does not appear to have the beta p-values as
> an option.  Can anyone help? Thanks.
Here is a quick and dirty solution. You'll need to modify the 
calculation of p if the sample is too small to justify a z 
approximation, i.e. use the t distribution instead.

* Run the regression first, then run this
mat b = e(b)
mat v = e(V)
local k = colsof(b)
mat z = J(1, `k', 0)
mat p = J(1, `k', 0)

forval j = 1/`k' {
        local z  =  b[1,`j'] / sqrt( v[`j', `j'] )
        local p = 2* (1 - normal(abs(`z' )) )
        mat z[1,`j'] = `z'
        mat p[1,`j'] = `p'
}
mat list z
mat list p


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Richard Williams, Notre Dame Dept of Sociology
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