standard deviation


Definition of standard deviation

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 children who got ARC Core did significantly better on a standardized test of reading comprehension—0.17 of a standard deviation, in research-speak. Natalie Wexler, Forbes, 8 Sep. 2021 Whereas gold bullion and the S&P 500 have a standard deviation of ±1% over a single trading day, Bitcoin has one closer to ±4%. Frank Holmes, Forbes, 25 Oct. 2021 The metrics are expressed as three-digit indexes, where 100 is average, 110 is one standard deviation above average, 120 is two standard deviations better than average, and so on. Paul Daugherty, The Enquirer, 31 Mar. 2022 The eight All-Stars scored at least one standard deviation above the mean in all five categories, meaning their scores were in the top 15% to 20% for more than 800 companies studied by Drucker. WSJ, 15 Feb. 2022 According to a study from Schaeffer's Senior Quantitative Analyst Rocky White, AA has come within one standard deviation of this trendline six other times over the past three years. Schaeffer's Investment Research, Forbes, 17 Mar. 2022 FedEx stock is within one standard deviation of its 40-day moving average. Schaeffer's Investment Research, Forbes, 19 Jan. 2022 His grounder rate was also over a full standard deviation above average. Tony Blengino, Forbes, 25 Jan. 2022 More specifically, GoPro stock just came within one standard deviation of its 40-day moving average, after some time spent above this trendline. Schaeffer's Investment Research, Forbes, 29 Dec. 2021 See More

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'standard deviation.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

First Known Use of standard deviation

1894, in the meaning defined at sense 1

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The first known use of standard deviation was in 1894

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Last Updated

9 May 2022

Cite this Entry

“Standard deviation.” Dictionary, Merriam-Webster, Accessed 19 May. 2022.

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