I have a very basic question (just starting with R).
I have two datasets (xlsx files) with one variable (x) and 11 observations.
I need to combine these two tables to one table with the variable x (ending up with 22 observations and 1 variable).
But I still need to be able to distinguish which observations belonged to group1 and which to group2 --> so I guess I have to add a Factor like A for group1 and B for group 2.
How can I add this factor so that it remains with the values after combining/stacking the datasets?
Thanks already in advance!