## Rapidly Computing the Standard Deviation for a Fixed Period (Length of Data)

Wikipedia’s page for Standard Deviation presents a formula for rapidly calculating the standard deviation of a growing set of numbers:

[1] Q_{k} = Q_{k-1} + (x_{k} – A_{k-1})(x_{k} – A_{k}) where x_{k} is the kth element in the set and A_{k} is the mean of the first kth numbers.

The standard deviation squared of the first n numbers of a set is Q_{n} / n.

From this, it is easy … Read more

## List of MSN Gaming Zone Backgammon Cheaters

*[Update: MSN has removed Backgammon from its games. Probably because of the rampant cheating. For a more fair place to play Backgammon that minimizes the chance of cheating (particularly because of the availability of instant replays) try https://www.gameslush.com/backgammon]*

Figured I’d compile this list after seeing several cheaters that … Read more