Hi,
I have a dataset, where i need to calculate the mean of all the variables across x observations.
Every person can have several card_times per exam_time.
My dataset looks like this:
exam_time card_time id var1 var2 var3
1
2
3
4
.
I need to calculate the mean of var1 var2 var3 with the same exam_time creating a new dataset containing only the mean of the variables = one line per exam time.
Any suggestions?
Thanks