We were working hard at creating our own online mathematics refresher course but in the course of doing so I came across the site linked to below. This site is a positively superb one that provides a very straightforward and interactive way to get you skills brushed up before jumping into stats.
As you'll see when you start up the tutorial, it presents you with a "subway map" where each stop represents some kind of math you can brush up on. There is actually much more to this site than you need to know for the course. What I would suggest is that you do the whole "yellow line". Thus .. hit the following stops:
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