Compare several proportions

[Sourou Olodo]

Hello,
I have 3 dichotomous variables (0;1) for which I would like to know if there is a significant difference between the 3 proportions observed together. These variables are measured at time intervals t0, t1 and t2.

It is also required to do a chi2 test of trend between the 3 proportions.

I don't know how to do this with STATA, any help would be great.

Thank you for the availability.

[Joseph Coveney]

These variables are measured at time intervals t0, t1 and t2.

Are they measured on the same entities each time or are the entities different each time?

It is also required to do a chi2 test of trend between the 3 proportions.

It's not clear what you mean by this. It will be better for list members to help you, as well as better for yourself to conceive what your objective is more clearly, if you cast this test requirement in terms of a null-versus-alternative hypothesis pair, with say subscripted Greek letters representing the population parameters whose relationship is being quantitatively evaluated.