The Brier Score
A brief document outlining the basic mathematics of the Brier score.
Accompanying the above document is an interactive Scratch program that show the Brier Score is a proper scoring rule. That is, to optimize your Brier Score you must bet your true belief!
Forecasting Random Walks
A document that poses some scenarios for consideration about modeling time series data, and includes links to code to simulate and explore different kinds of change.