Cigarettes Cause Lung Cancer?

When you see a statistic reported in the news, like "10% of University of California Berkeley students were homeless this year," how do you evaluate it? You shouldn't blindly accept every statistic you read. But neither should you reject everything that sounds surprising. Tim Harford, economist and author of The Data Detective: Ten Easy Rules to Make Sense of Statistics, talks about the heuristics he recommends using, and the mistakes people tend to make.