I did some quick searching and like you I found it very difficult to find any actual numbers though I did come across this useful article that explains some considerations you will want to think about when it comes to licensing all sorts of IP.
Your best bet would be to reach out to several studios, be them Movie, TV, Video Game, etc. and explain to them that you are writing a paper for school and ask what they do when it comes to determining cost for licensing and if they would be able to provide you specific examples (though I have a feeling those numbers are private - you might get lucky).