Standard deviation (SD)

The standard deviation shows how far values typically are from the mean. A small SD means the values are close together.

Example: Group "yes": M = 53.92, SD = 11.36. With a roughly normal distribution, about two thirds of the values lie between 42.6 and 65.3 points.

Caution: The SD describes how different the people are - not how precise the mean is. That is what the standard error and the confidence interval are for.