This is a programmitic answer to the question "what is CouchDB's reduce good for?"

For more details on the original question, see here:

http://tinyurl.com/reduce-std-dev

To run the example, you'll need the CouchRest gem installed

sudo gem install jchris-couchrest -s http://gems.github.com

then run these two commands in the root directory of this project:

ruby import.rb readings.txt
ruby query.rb