Hi,
I'm fairly new to Stata so I apologize if my question is basic. I am essentially trying to create a new variable by getting a weighted average of 20 variables (the syntax might eventually look like var1*a1+var*2+a2....var20*a20/(a1+a2+...a20). When I do this, it says that there are no observations.
I then tried to confirm that I was even able to add the variables a1, a2... but when I add them all it still says no observations. Why might this be the case?

The variable in question is a Likert-type survey question and there are 5 different levels (1,2,3,4,5).

Thank you,