“skewness”的概念、定义、翻译、参考文献-科学参考

skewness

Mathematics

The amount of asymmetry of a distribution. One measure of skewness is the coefficient of skewness, which is defined to be equal to μ‎₃/(μ‎₂)^3/2, where μ‎₂ and μ‎₃ are the second and third moments about the mean. This measure is zero if the distribution is symmetrical about the mean. If the distribution has a long tail to the left, as in the top figure, it is said to be skewed to the left and to have negative skewness, because the coefficient of skewness is negative. If the distribution has a long tail to the right, as in the second figure, it is said to be skewed to the right and to have positive skewness, because the coefficient of skewness is positive. A skew distribution is one that is skewed to the left or skewed to the right.

Skewed to the left
Skewed to the right

Geology and Earth Sciences

An expression of the degree of asymmetry shown on a frequency distribution. A non-skewed distribution is a perfect, normal (Gaussian) distribution. Grain-size distributions are skewed positively where larger particles are more numerous than fine ones, or negatively where finer particles exceed coarse within the distribution.

Economics

A measure of the degree of asymmetry of the distribution of a random variable; the standardized third moment of the distribution, defined as

$γ = E [{(X - μ)}^{3}] / σ^{3}$

where μ‎ is the mean and σ‎ is the standard deviation. For a symmetrical distribution γ‎ = 0 and the median of the distribution equals its mean. In a distribution with positive skewness the median is below the mean, and with negative skewness the median is above the mean. For example, the empirical distribution of income across the population in both developed and less developed countries exhibits positive skewness: a large proportion of income accrues to a small proportion of the population.

单词	skewness
释义	skewness Mathematics The amount of asymmetry of a distribution. One measure of skewness is the coefficient of skewness, which is defined to be equal to μ‎₃/(μ‎₂)^3/2, where μ‎₂ and μ‎₃ are the second and third moments about the mean. This measure is zero if the distribution is symmetrical about the mean. If the distribution has a long tail to the left, as in the top figure, it is said to be skewed to the left and to have negative skewness, because the coefficient of skewness is negative. If the distribution has a long tail to the right, as in the second figure, it is said to be skewed to the right and to have positive skewness, because the coefficient of skewness is positive. A skew distribution is one that is skewed to the left or skewed to the right. Skewed to the left Skewed to the right Geology and Earth Sciences An expression of the degree of asymmetry shown on a frequency distribution. A non-skewed distribution is a perfect, normal (Gaussian) distribution. Grain-size distributions are skewed positively where larger particles are more numerous than fine ones, or negatively where finer particles exceed coarse within the distribution. Economics A measure of the degree of asymmetry of the distribution of a random variable; the standardized third moment of the distribution, defined as $γ = E [{(X - μ)}^{3}] / σ^{3}$ where μ‎ is the mean and σ‎ is the standard deviation. For a symmetrical distribution γ‎ = 0 and the median of the distribution equals its mean. In a distribution with positive skewness the median is below the mean, and with negative skewness the median is above the mean. For example, the empirical distribution of income across the population in both developed and less developed countries exhibits positive skewness: a large proportion of income accrues to a small proportion of the population.
随便看	space motion sickness space of flows space participant Space Physics Data Facility spaceport space probe space programme space qualified space quantization space race Space Radar Laboratory spacer DNA space reddening space-reflection symmetry space research Space Science Board Space Science Data Operations Office Space Services Inc. SpaceShipOne space shuttle space shuttle main engine space sickness space simulator space station spacesuit