Might be just you and your group of friends. I know a lot of developers and none are musicians. That isn't to say there isn't a correlation or that there is one

Might be just you and your group of friends. I know a lot of developers and none are musicians. That isn't to say there isn't a correlation or that there is one but most people tend to have friends with similar interest. That could be why you're sending a trend amongst your friends that happen to exhibit these two traits. For example, among my friends, it seems common that most of the really good hackers tend to code and be avid runners. I'm sure there's no real correlation on that.