[mistermcgruff]

If you've got a college semester of linear algebra under your belt (or equivalent) and are pretty good with Excel, then the book is a good fit. Even the algebra can be optional if you're willing to use wikipedia liberally. I don't take for granted that the reader has a lot of background.

That said, there are parts in the book that are really quite hard. Hard in that they just take time to work through. Because the book is about learning all the steps that go into training models and doing analyses from scratch. But once you do it all from scratch once, you don't necessarily have to ever ever do it again.

It's taught in Excel for learning purposes, and then the last chapter moves you into R. Literally, the Holt Winters forecasting chapter of the book is 50 pages while in R it's the forecast package plus 3 lines of code.