Probability theory recall
The course builds on your probability theory / statistics knowledge, which is necessary to understand the course material.
If you feel you need to repeat some concepts, I find the material here very useful (both video and text are available): http://www.probabilitycourse.com/videos/videos.php.
Specifically, you should review (from the list of video lectures) Chapters 1,3,4, and 6.1.2.
You can find a shorter overview in the Virtamo notes, chapters 1 to 4.
To enforce that all students take the time and repeat the basics of probability theory, there is an early home assignment with exclusively probability theory problems.