Ben Orlin of Math With Bad Drawings explains the pitfalls of using summary statistics — mean, median, and mode — to make decisions in life. Aggregates like these are meant as wideout overviews. Look deeper for details.
Sketchy summary statistics
Life expectancy changes
The data goes back to 1960 and up to the most current estimates for 2009. Each line represents a country.
Real Chart Rules to Follow
There are rules—usually for specific chart types meant to be read in a specific way—that you shouldn’t break. When they are, everyone loses. This is that small handful.