I was going to write a blog posting on this topic, but then I found this excellent article written by The Writing Center of the University of North Carolina. Yes, maybe I wimped out, but this is really a good summary of how to look at data critically.
However, just to reinforce a couple points.
Don’t trust data because its quoted on one of your social media ‘friends’ posts. You may trust Bob, and Bob trusts Alex, who has always trusted Sanjay, who trusts Cindy, who trusts Cal, who has an agenda and is distorting the truth.
As the article points out, there are three ways to calculate the center of a data set (Mean, Median, Mode). Often those with an agenda choose the one that helps to make their point the best.
Finally, I am always suspicious when a data set makes me say ‘Yes! That’s just what I thought. I knew I was right.”
Am I falling for a biased study, because it matches my beliefs? Question yourself as much as you question others.