Newbie: Are there any sample files that are really really basic?

[Pito Salas]

I am trying to get up to speed and I am looking for examples even more simple than ./examples. For example, I have what I think would be a 4 column dataset as follows

User, Movie, Actual Rating, Predicted Rating

Which is the result of running a prediction algorithm against a test set.

I want simple stats like the average error (actual vs. predicted)

I think that would be a 3 line ruby program using this library but not sure exactly what the calls are, for example, what is to_scale?

Thanks!