Hi!
I am working on my final paper and could need som help.
What i'm trying to do is to investigate if a tax who was implemented on 2018 second quarter had any effect on total passengers traveling. I want to include GDP for the start period 2015 first quarter and interact that variable with my quarterly fix effects. That is, if the value of GDP for a country was 1300 in the first quarter of my data, I want to interact that with each quarterly dummy - this would give me a value that will exist for each quarter. How can I do it in Stata?