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
Example Sentences
Recent Examples on the Web In July of this year, the ratio surpassed the 200% threshold – representing more than a two standard deviation above its long-term trend. 
Nick Sargen, Forbes, 2 Sep. 2021 According to Schaeffer's Senior Quantitative Analyst Rocky White's latest study, MPC is within one standard deviation of its 160-day moving average. Schaeffer's Investment Research, Forbes, 6 July 2022 The subjects had an average age of 47 but spanned a wide spectrum, with a standard deviation of 12 years; 60 percent of them were female. Alex Hutchinson, Outside Online, 2 Feb. 2021 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 See More
Nick Sargen, Forbes, 2 Sep. 2021 According to Schaeffer's Senior Quantitative Analyst Rocky White's latest study, MPC is within one standard deviation of its 160-day moving average. Schaeffer's Investment Research, Forbes, 6 July 2022 The subjects had an average age of 47 but spanned a wide spectrum, with a standard deviation of 12 years; 60 percent of them were female. Alex Hutchinson, Outside Online, 2 Feb. 2021 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 See More Word History
First Known Use
1894, in the meaning defined at sense 1