When I first started grad school, I was pretty lost when it came to econometrics. I wondered why things were so difficult. Then I found out that there was a large gap between the statistics I knew, and the statistics I needed to know before starting econometrics. I read this book on my own, and it quickly taught me the stats I needed to know. It's very good for self study, since there are many worked out examples. The book is also relatively short, and is geared to get people up and running quickly. It seems designed for people in my situation. It's a prep course for graduate level econometrics. If you have done only basic statistics and econometrics in undergrad, definitely work through this stuff before you start grad school and apply the probability and statistics in this book to econometric models, especially if your grad dept, like mine, wrongly assumes that everybody knows this already and delves right into econometrics