Need help w code

[John Garcia]

Hi first of all I am very new to Stata and have to perform a test with multiple variables, so for example, prior a timestamp and after a timestamp for a specific illness

so like i'll run a nbreg x if y == 1, z == 2, how can i do this? because negative binomial won't run with multiple if's

i chose nbreg because of overdispersion in my data

my exercise asks me to test whether pre-timestamp number due to x have grown quicker compared to numbers due to y

[Daniel Feenberg]

Are you looking for

nbreg x if y==1&z==2

where & is the Stata AND operator, otherwise you may need to clarify your question.

[John Garcia]

Are you looking for

nbreg x if y==1&z==2

where & is the Stata AND operator, otherwise you may need to clarify your question.

I think its working, thank you!


Edit: p value comes out at . is that normal?