I’ve just put up the second in an ongoing series (I hope!) of articles on Oracle SQL’s built-in statistical functions. The topic is standard deviation. I introduce the concept and show one use of it in detecting wide variations that otherwise go unseen in summarized data. Here’s a link to the article:
It was a fun article to write. I’m very happy at the way the main example turned out, and I believe you’ll also enjoy it. I drew on some real life data from our National Oceanic and Atmospheric Administration. It is mean lake-level from the Great Lakes. Looking at the mean, you won’t “see” a quite notable event that standard deviation brings out in quite a startling manner. Some of the related links I’ve included are interesting as well.
The first article in the series is on the mean, which is to say it is on SQL’s AVG function. I thought that would be an easy article to write, but there was more to say than I had first realized. Link:
Arithmetic mean leads to several other interesting topics. One such is MEDIAN, which I plan to cover next, and then there is the harmonic mean and the geometric mean. The math behind them and how they are used is interesting. Look for articles on those topics at some future point.