Ask HN: Recommended Statistics Books/Topics for Founders?

I'm making more of an effort to devote time to learning subjects now that I believe will be especially important in the coming years - and as a founder I believe statistics are going to be especially important.

I'd love to hear from the HN crowd - which statistics topics may be especially useful? Also - I'm currently enrolled at Stanford so if there are specific classes there that you recommend - I'll probably take them!