definition of variance  and standard deviation in statistics
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- In statistics, the standard deviation is a very common measure of dispersion. Standard deviation measures how spread out the values in a data set are around the mean. More precisely, it is a measure of the average distance between the values of the data in the set and the mean.
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Standard deviation First, calculate the deviations of each data point from the mean, and square the result of each: The variance is the mean of these values: and the population standard deviation is equal to the square root of the variance: This formula is valid only if the eight values with which we began form the complete population.
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Glossary of Statistical Terms Variance Definition: The square of the standard deviation. A measure of the degree of spread among a set of values; a measure of the tendency of individual values to vary from the mean value.he square of the standard deviation. A measure of the degree of spread among a set of values; a measure of the tendency of individual values to vary from the mean value.
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Introduction Standard Deviation (Volatility) Introduction. Standard deviation is a statistical term that measures the amount of variability or dispersion around an average. Standard deviation is also a measure of volatility. Generally speaking, dispersion is the difference between the actual value and the average value. The larger this dispersion or variability is, the higher the standard deviation. The smaller this dispersion or variability is, the lower the standard deviation.
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- Statistics and Probability Dictionary. Select a term from the dropdown text box. The online statistics glossary will display a definition, plus links to other related web pages. Select term: Variance. The variance is a numerical value used to indicate how widely individuals in a group vary. If individual observations vary greatly from the group mean, the variance is big; and vice versa. It is important to distinguish between the variance of a population and the variance of a sample.
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- DEFINITION of 'Variance'. A measurement of the spread between numbers in a data set. The variance measures how far each number in the set is from the mean.
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Variance and standard deviation We know that variance is a measure of how spread out a data set is. It is calculated as the average squared deviation of each number from the mean of a data set. For example, for the numbers 1, 2, and 3 the mean is 2 and the variance is 0.667.he standard deviation for a discrete variable made up of n observations is the positive square root of the variance and is defined as: Use this step-by-step approach to find the standard deviation for a discrete variable. 1  Calculate the mean. 2  Subtract the mean from each observation.
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- DEFINITION of 'Standard Deviation'. 1. A measure of the dispersion of a set of data from its mean. The more spread apart the data, the higher the deviation. Standard deviation is calculated as the square root of variance.EFINITION of 'Standard Deviation'. 1. A measure of the dispersion of a set of data from its mean. The more spread apart the data, the higher the deviation. Standard deviation is calculated as the square root of variance.
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Variance and standard deviation Variability can also be defined in terms of how close the scores in the distribution are to the middle of the distribution. Using the mean as the measure of the middle of the distribution, the variance is defined as the average squared difference of the scores from the mean.
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Range Variance and Standard Deviation. By far the most commonly used measures of dispersion in the social sciences are variance and standard deviation. Variance is the average squared difference of scores from the mean score of a distribution. Standard deviation is the square root of the variance.
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Ch. 5 Statistical Measurement Tools DEFINITION of 'Standard Deviation'. 1. A measure of the dispersion of a set of data from its mean. The more spread apart the data, the higher the deviation. Standard deviation is calculated as the square root of variance.2. In finance, standard deviation is applied to the annual rate of return of an investment to measure the investment's volatility. measure of the dispersion of a set of data from its mean. The more spread apart the data, the higher the deviation. Standard deviation is calculated as the square root of variance.
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How to Calculate Standard Deviation, Variance - Definition, Formula, Example How to Calculate Standard Deviation, Variance - Definition, Formula, Example. Standard deviation is a statistical measure of spread or variability.The standard deviation is the root mean square (RMS) deviation of the values from their arithmetic mean. The square of the standard deviation. A measure of the degree of spread among a set of values; a measure of the tendency of individual values to vary from the mean value.
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book Jazz. the total repertoire of a band. a script or story for a play. a record of bets, as on a horse race. Cards. the number of basic tricks or cards that must be taken before any trick or card counts in the score. a set or packet of tickets, checks, stamps, matches, etc., bound together like a book.
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Contents: Standard Deviation vs Variance A variance or standard deviation of zero indicates that all the values are identical. Variance is the mean of the squares of the deviations (i.e., difference in values from the mean), and the standard deviation is the square root of that variance.Standard deviation is used to identify outliers in the data.iffen › Science › Statistics. Standard deviation and variance are statistical measures of dispersion of data, i.e., they represent how much variation there is from the average, or to what extent the values typically deviate from the mean (average) .
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Population vs. Sample Variance and Standard Deviation Variance is defined and calculated as the average squared deviation from the mean. Standard deviation is calculated as the square root of variance or in full definition, standard deviation is the square root of the average squared deviation from the mean.opulation vs. Sample Variance and Standard Deviation. When calculating variance and standard deviation, it is important to know whether we are calculating them for the whole population using all the data, or we are calculation them using only a sample of data.
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What is Standard Deviation? Standard Deviation Definition. Standard Deviation is a statistical term used to measure the amount of variability or dispersion around an average. Technically it is a measure of volatility.Dispersion is the difference between the actual and the average value.The larger this dispersion or variability is, the higher is the standard deviation.tandard Deviation Definition. Standard Deviation is a statistical term used to measure the amount of variability or dispersion around an average. Technically it is a measure of volatility.
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standard deviation standard deviation. a measure of the dispersal of a random variable; the square root of the average squared deviation from the mean. For data that have a normal distribution about 68% of the data points fall within one standard deviation from the mean and 95% fall within two standard deviations. Symbol is σ.tandard deviation (SD) the dispersion of a random variable; a measure of the amount by which each value deviates from the mean. It is equal to the square root of the variance.
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Variance and Standard Deviation So, the variance is 6.8. And the standard deviation is the square root of the variance, which is 2.61. What this means is that, on average, you and your friends are 2.61 years apart in age. References. Frankfort-Nachmias, C. & Leon-Guerrero, A. (2006). Social Statistics for a Diverse Society.
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variance Statistics: The arithmetic mean of the squares of the deviations of all values in a set of numbers from their arithmetic mean. Variance and its square root (the standard deviation) are of fundamental importance as a measure of dispersion.
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What is 'Standard Deviation' Standard deviation is calculated based on the mean. The distance of each data point from the mean is squared, summed and averaged to find the variance. Or to put it another way: Variance is derived by taking the mean of the data points, subtracting the mean from each data point individually, squaring each of these results and then taking another mean of these squares.
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Standard Deviation And Variance Sample standard deviation is the square root of sample variance: (8.14)1/2 = 2.85%. In fact, standard deviation is so widely used because, unlike variance, it is expressed in the same units as the original data, so it is easy to interpret, and can be used on distribution graphs (e.g. the normal distribution).
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Standard Deviation and Variance Standard Deviation and Variance. Deviation just means how far from the normal. Standard Deviation. The Standard Deviation is a measure of how spread out numbers are. Its symbol is σ (the greek letter sigma) The formula is easy: it is the square root of the Variance.
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Variance & Standard Deviation Both the variance and the standard deviation meet these three criteria for normally-distributed (symmetric, bell-curve) data sets. The variance (σ2) is a measure of how far each value in the data set is from the mean. Here is how it is defined: Subtract the mean from each value in the data.
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- standard deviation. n. Symbol σ. A statistic used as a measure of the dispersion or variation in a distribution, equal to the square root of the arithmetic mean of the squares of the deviations from the arithmetic mean.tandard deviation (SD) the dispersion of a random variable; a measure of the amount by which each value deviates from the mean. It is equal to the square root of the variance.
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- Standard Deviation and Variance A commonly used measure of dispersion is the standard deviation, which is simply the square root of the variance. The variance of a data set is calculated by taking the arithmetic mean of the squared differences between each value and the mean value.he population standard deviation is the square root of this value. The variance of a sampled subset of observations is calculated in a similar manner, using the appropriate notation for sample mean and number of observations.
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Standard deviation Standard deviation. Standard deviation is a statistical measurement of how far a variable quantity, such as the price of a stock, moves above or below its average value. The wider the range, which means the greater the standard deviation, the riskier an investment is considered to be.
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Expected Return, Variance And Standard Deviation Of A Portfolio Variance. Variance (σ 2) is a measure of the dispersion of a set of data points around their mean value. In other words, variance is a mathematical expectation of the average squared deviations from the mean. It is computed by finding the probability-weighted average of squared deviations from the expected value. Variance measures the variability from an average (volatility).