Statistics are obtained in a variety of ways: by looking at records (e.g., birth and death records from a government agency, hospital, or church), by conducting surveys or polls, by observation (e.g., counting the number of electric cars that pass the corner of Main and Third Street), or by inference (if sales of diapers are going up, the birth rat

Be wary, though, of the way news media use the word “significant,” because to statisticians it doesn’t mean “noteworthy.” In statistics, the word “significant” means that the results passed mathematical tests such as t-tests, chi-square tests, regression, and principal components analysis (there are hundreds). Statistical significance tests quantif

The famous adage is that “correlation does not imply causation.” In formal logic there are two formulations of this rule: 1) Post hoc, ergo propter hoc (after this, therefore because of this). This is a logical fallacy that arises from thinking that just because one thing (Y) occurs after another (X), that X caused Y. People typically brush their t

Sometimes, the numbers are simply wrong, and it’s often easiest to start out by conducting some quick plausibility checks. After that, even if the numbers pass plausibility, three kinds of errors can lead you to believe things that aren’t so: how the numbers were collected, how they were interpreted, and how they were presented graphically.

Sometimes, the numbers are simply wrong, and it’s often easiest to start out by conducting some quick plausibility checks. After that, even if the numbers pass plausibility, three kinds of errors can lead you to believe things that aren’t so: how the numbers were collected, how they were interpreted, and how they were presented graphically.