With raid 0 you can theoretically get twice the read and write performance, but in practice that really depends on the workload. Raid 1 will not give you additional write performance, and I'm not sure whether it will give you extra read performance (it may read from both disks, but I don't know if it does).
When it comes to raid 5/6, that depends on a lot more than just the number of disks. Each read or write will result in at least two (three for raid 6) disks being used, and you also need computing resources (CPU or raid card) to calculate and verify the parity.
And all this leaves out (battery backed) write cache on the raid controller. That can cause an enormous performance increase as well (in fact, many of my databases wouldn't run without one!), and this increase is not related very much to raid level or number of disks.
So the only way to find an actual answer to your question is to try it out, tune the cache settings and tune your filesystem. No theoretical answer has any possibility of being correct, as most of the behaviour depends heavily on the application and configuration.