I'd echo UNM2009. I got around 90% correct (dipping down to 80% with the chapters near the end of the day)
I'm thinking the questions on the real thing won't be so clear cut. (Some are detail oriented but for the most part, I found the questions to be quite simple. Of course, it's entirely possible I feel this way because I just finished reading the chapter. Ask me to complete the same questions again in 3 weeks and I'll probably have no idea of what I'm doing)
But I'd recommend trying your hand at a couple. It's nice to have some way of reviewing what you just read and making sure you aren't just gliding right thru the material.