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  2. Coefficient of variation - Wikipedia

    en.wikipedia.org/wiki/Coefficient_of_variation

    Anonymity – c v is independent of the ordering of the list x. This follows from the fact that the variance and mean are independent of the ordering of x. Scale invariance: c v (x) = c v (αx) where α is a real number. [22] Population independence – If {x,x} is the list x appended to itself, then c v ({x,x}) = c v (x). This follows from the ...

  3. Variation ratio - Wikipedia

    en.wikipedia.org/wiki/Variation_ratio

    The variation ratio is a simple measure of statistical dispersion in nominal distributions; it is the simplest measure of qualitative variation. It is defined as the proportion of cases which are not in the mode category:

  4. Hutchinson's rule - Wikipedia

    en.wikipedia.org/wiki/Hutchinson's_rule

    Hutchinson showed that the average body size ratio in species of the same genus that belong to the same community and use the same resource is about 1.3 (from 1.1 to 1.4) and the respective body weight ratio is 2. This empirical pattern tells us that this rule does not apply to all organisms and ecological situations.

  5. Index of dispersion - Wikipedia

    en.wikipedia.org/wiki/Index_of_dispersion

    In probability theory and statistics, the index of dispersion, [1] dispersion index, coefficient of dispersion, relative variance, or variance-to-mean ratio (VMR), like the coefficient of variation, is a normalized measure of the dispersion of a probability distribution: it is a measure used to quantify whether a set of observed occurrences are clustered or dispersed compared to a standard ...

  6. Dimensionless numbers in fluid mechanics - Wikipedia

    en.wikipedia.org/wiki/Dimensionless_numbers_in...

    Dimensionless numbers (or characteristic numbers) have an important role in analyzing the behavior of fluids and their flow as well as in other transport phenomena. [1] They include the Reynolds and the Mach numbers, which describe as ratios the relative magnitude of fluid and physical system characteristics, such as density, viscosity, speed of sound, and flow speed.

  7. Silver ratio - Wikipedia

    en.wikipedia.org/wiki/Silver_ratio

    The silver ratio is a Pisot number, [5] the next quadratic Pisot number after the golden ratio. By definition of these numbers, the absolute value 2 − 1 {\displaystyle {\sqrt {2}}-1} of the algebraic conjugate is smaller than 1, thus powers of ⁠ σ {\displaystyle \sigma } ⁠ generate almost integers and the sequence σ n mod 1 ...

  8. Metallic mean - Wikipedia

    en.wikipedia.org/wiki/Metallic_mean

    Since the inverse of a metallic mean is less than 1, this formula implies that the quotient of two consecutive elements of such a sequence tends to the metallic mean, when k tends to the infinity. For example, if n = 1 , {\displaystyle n=1,} S n {\displaystyle S_{n}} is the golden ratio .

  9. Ratio estimator - Wikipedia

    en.wikipedia.org/wiki/Ratio_estimator

    The ratio estimator is a statistical estimator for the ratio of means of two random variables. Ratio estimates are biased and corrections must be made when they are used in experimental or survey work. The ratio estimates are asymmetrical and symmetrical tests such as the t test should not be used to generate confidence intervals.