[chuck-users] "Or"

Hallo, Once again, sorry for the rudimentary questions, but I can't seem to find the correct language for a very simple function: Instead of using Std.rand2f( ) for fluctuating volume or buf.rate, I'd like to simply have an either/or option. Play sample at a rate of 1.0 *or *1.5, randomly. The moses function (in pure data) was useful for this. Direction to the appropriate helpful would also be appreciated. Thanks so much, Tim