If you want to do advanced statistical analysis and data manipulation, relevant for macroeconomics and econometrics at post-graduate level, you need to understand matrix algebra.
This is one of those things that sounds worse than it is. As with everything, it will seem quite foreign and hard to begin but will become easier as you practice it, which trust me you will if you decide to go this way.
I have no intention of writing a post with a detailed guide on how to do it, but fortunately others did. So please check these out:
(If you have but any such website, please leave a comment with a link to it and I will consider adding it to the list above.)