Hello I am a Computer Science student and i am pursuing a project of data analysis, since I’m quite familiar with C++ due to my course I am interested in learning ROOT framework for this project can someone answer my following questions
Regarding 1, for a beginner, C++ and/or Python (you can write ROOT scripts on either). What you should know depends on what you want to do, but in general I’d say some basic programming and statistical analysis (descriptive stats, histograms, etc., possibly fitting too) are probably the most important things. Data in ROOT are usually handled with TTrees and/or RDataFrames, so you’ll also want to spend time learning about these (you can stick to either one of these, or both, whatever you prefer and works for you).
For 2 and anything documentation-related, go here:
https://root.cern/doc/master/
(on the top-left if you click on the “Version Master” dropdown you can go to the Docs of different versions). You can start with the ROOT Primer and check out the Intro Course and Tutorials. Many of the Doc pages for classes, etc have some explanations and examples, and all have links to the code if you want to see what’s going on. You can also ask on this Forum 
For 3, again depends on what you plan to do, from analysisng data to fitting, modelling. simulations,… but see above.
Additionally, I would recommend starting here: ROOT Manual.
You must have started at the home page and made it to the third icon “Forum”,
did you try the first one “Start” 
I believe all your questions are addressed there !
One pre-requisite might not have been mentioned there. You are a student so
must have an advisor . Is this advisor familiar with ROOT or any one in your
department ? If not what tools do they use ?
So now the question is what you your goal is. Do the data analysis or learn
a new tool . If it is the former, use the tool that the people around you use,
if it is latter, go forward unafraid and familiarize yourself with the tutorials …
-Eddy