The equation for the standard error is pretty basic right? It is:

,

where is the sample size and is the standard deviation of the data.

It measures potential error in an estimate that has been obtained from simple random sampling.

First published by the French mathematician Abraham de Moivre in 1730, Howard Wainer describes it as “The most dangerous equation”. Why? Not because it is dangerous to use, but because ignorance of it causes huge waste. Check out the five examples he provides here.

Learn to wield de Moivre’s equation to avoid the dangers of ignoring it.