Some additional data to work with on top of the stuff in the Internals Section
which has data sets and worked answers.
Retail Sales Data
zipped Excel file
A set of related time series which you can use to practice your analysis. I will mark any work submitted.
Some material to work with, though it doesn't cover all the answering questions in context.
Worksheets with a couple of exercises at each level.
This is quite a good explanation of the process for solving 3 x 3 equations by hand from http://www.slideshare.net