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
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Bond market volatility, as measured by the MOVE Index, surged more than 3 standard deviations above its recent average, reaching the highest level since the pandemic shock in March 2020.
—
George Calhoun, Forbes.com, 25 May 2025
Individual investors bought a net $4.1 billion worth of stocks on Monday from the open through 12:30 p.m. ET, the largest level ever for the time of day and a more than 11 standard deviation move, according to data from JPMorgan’s trading desk.
—Yun Li, CNBC, 20 May 2025
An Urban Institute study last year similarly found that improving math scores by 0.5 standard deviations for students up to age 12 was associated with larger increases in earnings by age 30 than other factors in the study.
—Bruce Rauner, The Orlando Sentinel, 22 Apr. 2025
Students exposed to it from kindergarten to the third grade gained a 0.25 standard deviation improvement in reading scores.
—Harry Anthony Patrinos, The Conversation, 26 Mar. 2025
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George Calhoun, Forbes.com, 25 May 2025
Individual investors bought a net $4.1 billion worth of stocks on Monday from the open through 12:30 p.m. ET, the largest level ever for the time of day and a more than 11 standard deviation move, according to data from JPMorgan’s trading desk.
—Yun Li, CNBC, 20 May 2025
An Urban Institute study last year similarly found that improving math scores by 0.5 standard deviations for students up to age 12 was associated with larger increases in earnings by age 30 than other factors in the study.
—Bruce Rauner, The Orlando Sentinel, 22 Apr. 2025
Students exposed to it from kindergarten to the third grade gained a 0.25 standard deviation improvement in reading scores.
—Harry Anthony Patrinos, The Conversation, 26 Mar. 2025
See All Example Sentences for standard deviation
Cite this Entry
“Standard deviation.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/standard%20deviation. Accessed 4 Jun. 2025.
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