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

Here are the average breath-hold times (BHT), plus and minus standard deviations, for the five holds: This progression is partly a result of the spleen’s extra red blood cells in action. —Alex Hutchinson, Outside Online, 16 Dec. 2024

In 1972 alone Allen was 2.62 standard deviations above league average OBP and 3.36 standard deviations above league average SLG for a total of 5.98. —Tony Blengino, Forbes, 10 Dec. 2024

Compounded with inconsistent datasets almost always full of excessive standard deviations and utter apathy toward innovation, a viable environmental policy simply cannot survive (let alone thrive) in such conditions. —Alexandra Harrell, Sourcing Journal, 6 Dec. 2024

Massive Pop Up Rate Santander’s 9.1% pop up rate was well over two full standard deviations above league average last season. —Tony Blengino, Forbes, 25 Nov. 2024

Word History

First Known Use

1895, in the meaning defined at sense 1

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