Favorite statistics calculator?

[STW]

I'm trying Lygea's HP15c emulator, but I wonder if there's a favorite stats calculator out there? What about a decent freeware/shareware calculator with a few scientific features?

If anyone's using the 15c emulator, is there a way to flip it? Are there options? I can't find anything that takes me to an options page.

Thanks,
Mitch