Hello everyone! I come to you because, having not had a teaching of statistics last year, I can not understand and use the statistical tests. I have to do a moderation analysis for my thesis. And I have some questions to ask you.

1. Can my moderate variable be categorical? (mine is divided into 4 groups)

2. Can I do a linear regression instead of using medmod to do a moderation?

3. Would it be possible to explain to me what I should conclude from the value of "estimate" "SE" "t" and "p" please?

Thanks a lot for your help !