standard deviation

American  

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.

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standard deviation British  

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

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standard deviation Scientific  

/ stăn′dərd /

1. 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.

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standard deviation Cultural  

1. 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.

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Discover More

About sixty-eight percent of the data are within one standard deviation of the mean.

Etymology

Origin of standard deviation

First recorded in 1920–25

Compare meaning

How does standard-deviation compare to similar and commonly confused words? Explore the most common comparisons:

• standard deviation vs. standard error

Example Sentences

Yet studies describe only “small effects, ranging from about plus or minus one-tenth of a standard deviation — or three or four points” on one of the federal National Assessment of Educational Progress tests.

From Washington Post

"The measurement is intriguing, but its statistical significance of 4.2 standard deviations has not reached the gold standard in particle physics data of 5," Loeb told Salon via email.

From Salon

If this value goes beyond five standard deviations from the theory—the gold standard for discovery in particle physics—it would be convincing evidence of new physics beyond the Standard Model.

From Scientific American

The standard deviation measures how much an individual county’s vote typically deviated from the national average; this measure was a bit lower in 2020 after rising steadily from 2000 to 2016.

From New York Times

Although it was hard, it paid off: the standard deviation of my blood sugar levels began to decrease and I felt healthier and happier.

From Nature