Try Our Apps

follow Dictionary.com

# standard deviation

noun, Statistics.
1.
a measure of dispersion in a frequency distribution, equal to the square root of the mean of the squares of the deviations from the arithmetic mean of the distribution.
Origin of standard deviation
1920-1925
First recorded in 1920-25
Dictionary.com Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2018.
Cite This Source
Examples from the Web for standard deviation
Historical Examples
• This is called the index of variability or "standard deviation."

William E. Kellicott
• For each measurement, the coefficient of variation, standard deviation and probable error were computed.

E. Raymond Hall
• And against the first target the accuracy observed was about .7 mils, in standard deviation.

The President's Commission on the Assassination of President Kennedy
British Dictionary definitions for standard deviation

## standard deviation

noun
1.
(statistics) a measure of dispersion obtained by extracting the square root of the mean of the squared deviations of the observed values from their mean in a frequency distribution
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
© William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
Cite This Source
standard deviation in Medicine

standard deviation n.
Symbol σ
A statistic used as a measure of the dispersion or variation in a distribution, equal to the square root of the arithmetic mean of the squares of the deviations from the arithmetic mean.

The American Heritage® Stedman's Medical Dictionary
Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
Cite This Source
standard deviation in Science
 standard deviation   (stān'dərd)    A statistic used as a measure of the dispersion or variation in a distribution, equal to the square root of the arithmetic mean of the squares of the deviations from the arithmetic mean.
The American Heritage® Science Dictionary
Copyright © 2002. Published by Houghton Mifflin. All rights reserved.
Cite This Source
standard deviation in Culture

### standard deviation definition

In statistics, a measure of how much the data in a certain collection are scattered around the mean. A low standard deviation means that the data are tightly clustered; a high standard deviation means that they are widely scattered.

Note: About sixty-eight percent of the data are within one standard deviation of the mean.
The New Dictionary of Cultural Literacy, Third Edition
Copyright © 2005 by Houghton Mifflin Company.
Published by Houghton Mifflin Company. All rights reserved.
Cite This Source

### Difficulty index for standard deviation

Few English speakers likely know this word

### Word Value for standard

10
11
Scrabble Words With Friends