Rook and Bishop value?

So I've recently started playing chess and, while I am still at a relatively low skill level, I enjoy getting better and learning from my mistakes. I've had a question for a long time: why are rooks given a higher value (5), compared to bishops (3)? When playing games it certainly feels like rooks are more powerful, but what is the exact reason why? Does it have something to do with their way of moving? If each piece is placed in a corner, for example, the rook can access 14 total squares while the bishop only 7. Could it also have something to do with open files and ranks being more common than open diagonals? I would like a response with more concrete evidence than my own thoughts. Good luck on your chess games!

A single rook can theoretically go to and control any square on the board whereas a single bishop can only use half the board (one colour square). This is my opinion anyway, not 'concrete evidence'.