Yeah the blog explained how the data is extrapolated. Basically its based on the cheapest paying airplane which typically are the most junior airplanes (which you are more likely to get hired for). Considering however that most people are qualified to be hired by any of these regionals, and how some people that have worked for companies like Horizon and Expressjet now work for companies like Great Lakes, it's interesting to see the difference.

Some are the same airplanes like this data is based on Horizon's Q400 pay and Colgan's Q400 pay.