Thank you Allin

Best regards2015-04-29 19:11 GMT+02:00 Allin Cottrell <cottrell@wfu.edu>:

On Wed, 29 Apr 2015, Simona De Lauretis wrote:

Dear Gretl users,

I have a question about system estimation and a (possible) bug report.

The question is: is it possible to include weights for observations when

estimating a system of equations in gretl (with sur method for example)?

I've read in the command reference that the supported estimators

are ols, tsls, sur, 3sls, fiml and liml. However, if I estimate the

system using the

"simultaneous equations" dialog box, there is also wls as one of the

proposed estimators

(but it's not possible to specify a weight variable, so maybe it does

not perform a

weighted regression after all).

Thanks for the report. The "wls" option has somehow slipped through undocumented, we need to fix that. But it's not intended that the user can supply weights, rather the idea is that weights are derived from

the relative variances of the error terms in the equations of the system. It's the same use of "wls" as in the systemfit package for R, in case you've come across that. See

http://cran.r-project.org/web/packages/systemfit/systemfit.pdf

for brief documentation.

The possible bug occurs after the estimation of a system using method SUR. In the results window, the command "Tests -> Normality of residuals" is active, but nothing happens when I click on it (gretl does not crash either).

I see what you mean. For some reason the normality test via the GUI was not hooked up to its "callback" to actually do the job (or actually, was hooked up only for models estimated on time-series data). That's now fixed in CVS and gretl snapshots.

Allin Cottrell

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