I would suggest taking Statistic, especially if its given under a limited schedule. For developing a breadth of knowledge to be a really competitive scientist, advanced mathematics courses are important. I didn't find them as much fun, and I didn't do well in them, but I know they're important. Recently, I've been trying to reteach myself statistics, and its not easy. Sure, I use linear regression all the time, but the theory behind it ... its not as simple as I thought.
That said, the other course is certainly interesting, and probably very worthwhile. Its really the biannual scheduling that chines it for me.