# On Using Standard Deviation or Standard Error of the Mean

## TL;DR

This paper explains the difference between standard deviation and standard error of the mean and their roles in scientific reporting.

## Contribution

Clarifies the distinct purposes of standard deviation and standard error of the mean in statistical reporting.

## Key findings

- Standard deviation reflects data dispersion in samples and populations.
- Standard error of the mean indicates the precision of the mean estimate.
- 95% confidence intervals are commonly reported and based on SEM.

## Abstract

The mean value is commonly used as a measure of central tendency. It is frequently reported along with either the standard deviation (SD) or the standard error of the mean (SEM). While the SD reflects the dispersion of the data in both the sample and population, SEM indicates the precision of the mean. SEM is not commonly used in reporting science; however, the 95% confidence interval, which is calculated based on SEM, is frequently reported in scientific literature.