standard deviation

noun

1

: a measure of the dispersion of a frequency distribution that is the square root of the arithmetic mean of the squares of the deviation of each of the class frequencies from the arithmetic mean of the frequency distribution

also : a similar quantity found by dividing by one less than the number of squares in the sum of squares instead of taking the arithmetic mean

2

: a parameter that indicates the way in which a probability function or a probability density function is centered around its mean and that is equal to the square root of the moment in which the deviation from the mean is squared

Examples of standard deviation in a Sentence

Recent Examples on the Web

The team based its claim on the fact that, at every age, the average height of children at each site was within half a standard deviation of the over-all average. —Manvir Singh, The New Yorker, 24 Mar. 2025

His walk rate of 5.8% in 2024 - while up from 4.0% the previous season, was over a full standard deviation better than league average. —Tony Blengino, Forbes, 5 Mar. 2025

The standard deviation for the S & P 500 for that month comes in at 6%. —Fred Imbert, CNBC, 3 Sep. 2024

This average sinker whiff rate was 5.0% last season, with a standard deviation of only 1.4%. —Tony Blengino, Forbes, 5 Mar. 2025

Word History

First Known Use

1895, in the meaning defined at sense 1

Rhymes for standard deviation

• abbreviation
• abomination
• acceleration
• accentuation
• accommodation
• accreditation
• acculturation
• accumulation
• acetylation
• adjudication
• administration
• adulteration

Kids Definition

standard deviation

noun

: the square root of the arithmetic mean of the squares of differences between the arithmetic mean of a frequency distribution and the values of the variable