Naked Statistics: Stripping the Dread from the Data

And it is not merely a hypothetical case. Evolutionary biologist Stephen Jay Gould was diagnosed with a form of cancer that had a median survival time of eight months; he died of a different and unrelated kind of cancer twenty years later.3 Gould subsequently wrote a famous article called “The Median Isn’t the Message,” in which he argued that his scientific knowledge of statistics saved him from the erroneous conclusion that he would necessarily be dead in eight months. The definition of the median tells us that half the patients will live at least eight months—and possibly much, much longer than that. The mortality distribution is “right-skewed,” which is more than a technicality if you happen to have the disease.4

selective school may be less motivated, less hardworking, or different in some other ways that we cannot observe.

best approach involves the least work! The optimal way to create any treatment and control group is to distribute the study participants randomly across the two groups.

ot more variation among

potentially positive outcome

kinds of experiments that we cannot perform on people.

Randomized, controlled experiments.

elevated alert but no extra law enforcement precaution

natural experiment here: What happens to ordinary crime on terrorism “high alert” days?

Data mining (too many variables).