I think the analysis may've been skewed by the outlying points. They are almost certainly "high leverage points"[1] and so possibly exert an undue influence on

I think the analysis may've been skewed by the outlying points. They are almost certainly "high leverage points"[1] and so possibly exert an undue influence on the final trend lines. [1]: http://en.wikipedia.org/wiki/Partial_leverage http://en.wikipedia.org/wiki/Partial_leverage