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Gini Coefficient In economics, the Gini coefficient Gini coefficient (/ˈdʒiːni/ JEEnee; sometimes expressed as a Gini ratio or a normalized Gini index) is a measure of statistical dispersion intended to represent the income or wealth distribution of a nation's residents, and is the most commonly used measurement of inequality. It was developed by the Italian statistician and sociologist Corrado Gini and published in his 1912 paper Variability and Mutability (Italian: Variabilità e mutabilità).[1][2] The Gini coefficient Gini coefficient measures the inequality among values of a frequency distribution (for example, levels of income). A Gini coefficient of zero expresses perfect equality, where all values are the same (for example, where everyone has the same income) [...More...]  "Gini Coefficient" on: Wikipedia Yahoo 

Economics Economics Economics (/ɛkəˈnɒmɪks, iːkə/)[1][2][3] is the social science that studies the production, distribution, and consumption of goods and services.[4] Economics Economics focuses on the behaviour and interactions of economic agents and how economies work. Microeconomics Microeconomics analyzes basic elements in the economy, including individual agents and markets, their interactions, and the outcomes of interactions. Individual agents may include, for example, households, firms, buyers, and sellers. Macroeconomics analyzes the entire economy (meaning aggregated production, consumption, savings, and investment) and issues affecting it, including unemployment of resources (labour, capital, and land), inflation, economic growth, and the public policies that address these issues (monetary, fiscal, and other policies) [...More...]  "Economics" on: Wikipedia Yahoo 

Lognormal Distribution In probability theory, a lognormal (or lognormal) distribution is a continuous probability distribution of a random variable whose logarithm is normally distributed. Thus, if the random variable X is lognormally distributed, then Y = ln(X) has a normal distribution. Likewise, if Y has a normal distribution, then the exponential function of Y, X = exp(Y), has a lognormal distribution. A random variable which is lognormally distributed takes only positive real values. The distribution is occasionally referred to as the Galton distribution or Galton's distribution, after Francis Galton.[1] The lognormal distribution also has been associated with other names, such as McAlister, Gibrat and Cobb–Douglas.[1] A lognormal process is the statistical realization of the multiplicative product of many independent random variables, each of which is positive. This is justified by considering the central limit theorem in the log domain [...More...]  "Lognormal Distribution" on: Wikipedia Yahoo 

Cumulative Distribution Function In probability theory and statistics, the cumulative distribution function (CDF, also cumulative density function) of a realvalued random variable X, or just distribution function of X, evaluated at x, is the probability that X will take a value less than or equal to x. In the case of a continuous distribution, it gives the area under the probability density function from minus infinity to x [...More...]  "Cumulative Distribution Function" on: Wikipedia Yahoo 

Integral In mathematics, an integral assigns numbers to functions in a way that can describe displacement, area, volume, and other concepts that arise by combining infinitesimal data. Integration is one of the two main operations of calculus, with its inverse, differentiation, being the other. Given a function f of a real variable x and an interval [a, b] of the real line, the definite integral ∫ a b f ( x ) d x displaystyle int _ a ^ b !f(x),dx is defined informally as the signed area of the region in the xyplane that is bounded by the graph of f, the xaxis and the vertical lines x = a and x = b. The area above the xaxis adds to the total and that below the xaxis subtracts from the total. Roughly speaking, the operation of integration is the reverse of differentiation [...More...]  "Integral" on: Wikipedia Yahoo 

Integration By Parts In calculus, and more generally in mathematical analysis, integration by parts or partial integration is a process that finds the integral of a product of functions in terms of the integral of their derivative and antiderivative. It is frequently used to transform the antiderivative of a product of functions into an antiderivative for which a solution can be more easily found [...More...]  "Integration By Parts" on: Wikipedia Yahoo 

Quantile Function In probability and statistics, the quantile function specifies, for a given probability in the probability distribution of a random variable, the value at which the probability of the random variable is less than or equal to the given probability [...More...]  "Quantile Function" on: Wikipedia Yahoo 

Lognormal Distribution In probability theory, a lognormal (or lognormal) distribution is a continuous probability distribution of a random variable whose logarithm is normally distributed. Thus, if the random variable X is lognormally distributed, then Y = ln(X) has a normal distribution. Likewise, if Y has a normal distribution, then the exponential function of Y, X = exp(Y), has a lognormal distribution. A random variable which is lognormally distributed takes only positive real values. The distribution is occasionally referred to as the Galton distribution or Galton's distribution, after Francis Galton.[1] The lognormal distribution also has been associated with other names, such as McAlister, Gibrat and Cobb–Douglas.[1] A lognormal process is the statistical realization of the multiplicative product of many independent random variables, each of which is positive. This is justified by considering the central limit theorem in the log domain [...More...]  "Lognormal Distribution" on: Wikipedia Yahoo 

Error Function In mathematics, the error function (also called the Gauss error function) is a special function (nonelementary) of sigmoid shape that occurs in probability, statistics, and partial differential equations describing diffusion [...More...]  "Error Function" on: Wikipedia Yahoo 

Dirac Delta Function In mathematics, the Dirac delta function, or δ function, is a generalized function, or distribution that was historically introduced by the physicist Paul Dirac Paul Dirac for modelling the density of an idealized point mass or point charge, as a function that is equal to zero everywhere except for zero and whose integral over the entire real line is equal to one.[1][2][3] As there is no function that has these properties, the computations that were done by the theoretical physicists appeared to mathematicians as nonsense, until the introduction of distributions by Laurent Schwartz, for formalizing and validating mathematically these computations [...More...]  "Dirac Delta Function" on: Wikipedia Yahoo 

Uniform Distribution (continuous) In probability theory and statistics, the continuous uniform distribution or rectangular distribution is a family of symmetric probability distributions such that for each member of the family, all intervals of the same length on the distribution's support are equally probable. The support is defined by the two parameters, a and b, which are its minimum and maximum values. The distribution is often abbreviated U(a,b) [...More...]  "Uniform Distribution (continuous)" on: Wikipedia Yahoo 

Exponential Distribution In probability theory and statistics, the exponential distribution (also known as negative exponential distribution) is the probability distribution that describes the time between events in a Poisson point process, i.e., a process in which events occur continuously and independently at a constant average rate. It is a particular case of the gamma distribution. It is the continuous analogue of the geometric distribution, and it has the key property of being memoryless [...More...]  "Exponential Distribution" on: Wikipedia Yahoo 

Chisquared Distribution In probability theory and statistics, the chisquared distribution (also chisquare or χ2distribution) with k degrees of freedom is the distribution of a sum of the squares of k independent standard normal random variables. The chisquare distribution is a special case of the gamma distribution and is one of the most widely used probability distributions in inferential statistics, e [...More...]  "Chisquared Distribution" on: Wikipedia Yahoo 

Normalization (statistics) In statistics and applications of statistics, normalization can have a range of meanings.[1] In the simplest cases, normalization of ratings means adjusting values measured on different scales to a notionally common scale, often prior to averaging. In more complicated cases, normalization may refer to more sophisticated adjustments where the intention is to bring the entire probability distributions of adjusted values into alignment. In the case of normalization of scores in educational assessment, there may be an intention to align distributions to a normal distribution [...More...]  "Normalization (statistics)" on: Wikipedia Yahoo 

Gamma Distribution In probability theory and statistics, the gamma distribution is a twoparameter family of continuous probability distributions. The exponential distribution, Erlang distribution, and chisquared distribution are special cases of the gamma distribution [...More...]  "Gamma Distribution" on: Wikipedia Yahoo 

Weibull Distribution In probability theory and statistics, the Weibull distribution /ˈveɪbʊl/ is a continuous probability distribution [...More...]  "Weibull Distribution" on: Wikipedia Yahoo 