Heh, a comment about this survey. I realize this is probably just an excercise in statistics. At least, I hope that's all it is, because this data seems kinda useless.
If you do statistics, it's important to plan ahead - you know, figure out what kind of data you want. How is it gonna be comparable? Do you have a control?
It seems you want to somehow correlate understanding of maths with understanding or skill at music. Smells like hidden variables if you ask me.
