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st: bivariate probit problem with no (0,0) observations


From   Pierre Lafaye de Micheaux <plafaye@club-internet.fr>
To   statalist@hsphsun2.harvard.edu
Subject   st: bivariate probit problem with no (0,0) observations
Date   Mon, 26 Sep 2005 16:33:09 +0000

Dear Stata gurus,

Here is the experiment we are conducting:

Laboratory rats are smelling some kind of odour and then we measure their neuronal activity. We then observe the presence/absence of gamma or beta waves.
But you should always have some kind of wave (beta or gamma). The absence of the two waves means a failure in the experiment.
So you only have (1,1), (1,0) and (0,1) data.
And never (0,0) data. (But when the rat is dead, or the electrod badly placed, etc ...).

We are interested in modeling the presence/absence of gamma or beta waves as a function of odour's characteristics.

We then wanted to use a bivariate probit analysis (through biprobit for example) but the fact that there is no (0,0) observations (structural zero case) seems to be a problem.

Do you know how we could handle this?

Best regards,

Pierre

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