Group variables for my thesis

[Daaki Sadat]

Hello guys,
I am currently running a panel ARDL study. I have 40 countries in SSA as my case study. However, I want to classify them into:
1). Oil and coal exporting and Non-oil and coal exporting
2). Following Agtmael (1981), categorize emerging and least developed bases on per capita GDP.

How can i do this?

[Carlo Lazzaro]

Daaki:
-posting and reposting the same query trying to increase your chances of getting the desired replies, usually produces the opposite effect;
-your question is way too broad. Please see the FAQ on how to post more effectively;
-as per FAQ again, please note that this is a multidiscipinary forum. Hence, full reference please. I do ignore the contribution you quoted (and I'd bet that this holds for many others contributors to this forum).