Yeah, I just read the introduction materials and then did the first week, it took maybe an hour on the high side. I watched the videos, looked at the notes (it is basically the same as the video) and took the quizzes. The quizzes are only a few questions each and they are multiple choice. I agree with Sizzle that some of them are worded a bit tricky but not really difficult if you take your time.
The case study took me the longest because my initial answer was like... fifteen words, LOL. And I had to figure out how to elaborate a bit.
Sillysally, it's free! Lots of universities are doing similar things these days... offering up their courses for free. You don't get college credit or anything, but you do get to learn. =>