scholarly journals Kurtosis

Psychology ◽  
2021 ◽  
Author(s):  
Zhiyong Zhang ◽  
Wen Qu
Keyword(s):  
Probability Distribution ◽  
Normal Distribution ◽  
Random Variables ◽  
Random Variable ◽  
Quantitative Psychology ◽  
Psychometric Models ◽  
Univariate Distribution

In statistics, kurtosis is a measure of the probability distribution of a random variable or a vector of random variables. As mean measures the centrality and variance measures the spreadness of a probability distribution, kurtosis measures the tailedness of the distribution. Kurtosis for a univariate distribution was first introduced by Karl Pearson in 1905. Kurtosis, together with skewness, is widely used to quantify the non-normality—the deviation from a normal distribution—of a distribution. In psychology, kurtosis has often been studied in the field of quantitative psychology to evaluate its effects on psychometric models.

scholarly journals Analysis of the folded normal distribution of a random variable

2021 ◽  
pp. 111-122
Author(s):  
Степан Алексеевич Рогонов ◽  
Илья Сергеевич Солдатенко
Keyword(s):  
Probability Distribution ◽  
Analytical Solution ◽  
Normal Distribution ◽  
Random Variables ◽  
Random Variable ◽  
Point Of View ◽  
Practical Solution ◽  
Absolute Value ◽  
Actual Error ◽  
Folded Normal Distribution

Анализ поведения случайных величин после различных преобразований можно применять при решении многих нетривиальных задач. В частности, решения, которые невозможно выразить аналитически, с точки зрения практической применимости способны давать результаты с точностью, достаточной для вычислений, вынося невыразимую невязку аналитического решения далеко за рамки требуемой погрешности. В настоящей работе исследовано поведение модуля нормально распределенной случайной величины и выяснено, при каких условиях можно пренебречь операцией взятия абсолютного значения и аппроксимировать модуль случайной величины {\it похожим} распределением вероятностей. The analysis of the behavior of random variables after various transformations can be used in the practical solution of many non-trivial problems. In particular, solutions that cannot be expressed purely analytically, from the point of view of practical applicability, are able to give results with accuracy sufficient for real calculations, taking the inexpressible discrepancy of the analytical solution far beyond the actual error. In this paper, the behavior of the modulus of a normally distributed random variable is investigated and it is found out under what conditions it is possible to neglect the operation of taking an absolute value and approximate the modulus of a random variable with a {\it similar} probability distribution.

Introduction to Information Theory

2014 ◽  
Author(s):  
M. Vidyasagar
Keyword(s):  
Information Theory ◽  
Probability Distribution ◽  
Relative Entropy ◽  
Probability Distributions ◽  
Random Variables ◽  
Conditional Entropy ◽  
Random Variable ◽  
Entropy Function ◽  
Concave Functions ◽  
Leibler Divergence

This chapter provides an introduction to some elementary aspects of information theory, including entropy in its various forms. Entropy refers to the level of uncertainty associated with a random variable (or more precisely, the probability distribution of the random variable). When there are two or more random variables, it is worthwhile to study the conditional entropy of one random variable with respect to another. The last concept is relative entropy, also known as the Kullback–Leibler divergence, which measures the “disparity” between two probability distributions. The chapter first considers convex and concave functions before discussing the properties of the entropy function, conditional entropy, uniqueness of the entropy function, and the Kullback–Leibler divergence.

scholarly journals A refinement of normal approximation to Poisson binomial

2005 ◽  
Vol 2005 (5) ◽  
pp. 717-728 ◽  
Author(s):  
K. Neammanee
Keyword(s):  
Normal Distribution ◽  
Normal Approximation ◽  
Random Variables ◽  
Random Variable ◽  
Standard Normal Distribution ◽  
Bernoulli Random Variables ◽  
Binomial Random Variable ◽  
Standard Normal ◽  
Correction Terms ◽  
Better Than

LetX1,X2,…,Xnbe independent Bernoulli random variables withP(Xj=1)=1−P(Xj=0)=pjand letSn:=X1+X2+⋯+Xn.Snis called a Poisson binomial random variable and it is well known that the distribution of a Poisson binomial random variable can be approximated by the standard normal distribution. In this paper, we use Taylor's formula to improve the approximation by adding some correction terms. Our result is better than before and is of order1/nin the casep1=p2=⋯=pn.

scholarly journals Probabalistic modelling of the results of economic activity as a function of random values

2020 ◽  
pp. 102-112
Author(s):  
Olesya Martyniuk ◽  
Stepan Popina ◽  
Serhii Martyniuk
Keyword(s):  
Mathematical Modeling ◽  
Distribution Function ◽  
Probability Distribution ◽  
Economic Activity ◽  
Probability Distribution Function ◽  
Random Variables ◽  
Economic Structure ◽  
Random Variable ◽  
Independent Random Variables ◽  
Research Results

Introduction. Mathematical modeling of economic processes is necessary for the unambiguous formulation and solution of the problem. In the economic sphere this is the most important aspect of the activity of any enterprise, for which economic-mathematical modeling is the tool that allows to make adequate decisions. However, economic indicators that are factors of a model are usually random variables. An economic-mathematical model is proposed for calculating the probability distribution function of the result of economic activity on the basis of the known dependence of this result on factors influencing it and density of probability distribution of these factors. Methods. The formula was used to calculate the random variable probability distribution function, which is a function of other independent random variables. The method of estimation of basic numerical characteristics of the investigated functions of random variables is proposed: mathematical expectation that in the probabilistic sense is the average value of the result of functioning of the economic structure, as well as its variance. The upper bound of the variation of the effective feature is indicated. Results. The cases of linear and power functions of two independent variables are investigated. Different cases of two-dimensional domain of possible values of indicators, which are continuous random variables, are considered. The application of research results to production functions is considered. Examples of estimating the probability distribution function of a random variable are offered. Conclusions. The research results allow in the probabilistic sense to estimate the result of the economic structure activity on the basis of the probabilistic distributions of the values of the dependent variables. The prospect of further research is to apply indirect control over economic performance based on economic and mathematical modeling.

scholarly journals Theorizing Probability Distribution in Applied Statistics

2020 ◽  
Vol 1 (1) ◽  
pp. 79-95
Author(s):  
Indra Malakar
Keyword(s):  
Probability Distribution ◽  
Normal Distribution ◽  
Poisson Distribution ◽  
Binomial Distribution ◽  
Identical Condition ◽  
Random Variable ◽  
Fixed Number ◽  
Theoretical Knowledge ◽  
Applied Statistics ◽  
Discrete Random Variable

This paper investigates into theoretical knowledge on probability distribution and the application of binomial, poisson and normal distribution. Binomial distribution is widely used discrete random variable when the trails are repeated under identical condition for fixed number of times and when there are only two possible outcomes whereas poisson distribution is for discrete random variable for which the probability of occurrence of an event is small and the total number of possible cases is very large and normal distribution is limiting form of binomial distribution and used when the number of cases is infinitely large and probabilities of success and failure is almost equal.

scholarly journals Reliability analysis of planar steel trusses based on p-box models

Vestnik MGSU ◽  
2021 ◽  
pp. 153-167
Author(s):  
Anastasia A. Soloveva ◽  
Sergey A. Solovev
Keyword(s):  
Probability Distribution ◽  
Reliability Analysis ◽  
Statistical Data ◽  
Random Variables ◽  
Random Variable ◽  
Distribution Functions ◽  
Structural Elements ◽  
Limit States ◽  
Load Model ◽  
Box Models

Introduction. The development of probabilistic approaches to the assessment of mechanical safety of bearing structural elements is one of the most relevant areas of research in the construction industry. In this research, probabilistic methods are developed to perform the reliability analysis of steel truss elements using the p-box (probability box) approach. This approach ensures a more conservative (interval-based) reliability assessment made within the framework of attaining practical objectives of the reliability analysis of planar trusses and their elements. The truss is analyzed as a provisional sequential mechanical system (in the language of the theory of reliability) consisting of elements that represent reliability values for each individual bar and truss node in terms of all criteria of limit states. Materials and methods. The co-authors suggest using p-blocks consisting of two boundary distribution functions designated for modeling random variables in the mathematical models of limit states performed within the framework of the truss reliability analysis instead of independent true functions of the probability distribution of random variables. Boundary distribution functions produce a probability distribution domain in which a true distribution function of a random variable is located. However this function is unknown in advance due to the aleatory and epistemic uncertainty. The choice of a p-block for modeling a random variable will depend on the type and amount of statistical information about the random variable. Results. The probabilistic snow load model and the numerical simulation of tests of steel samples of truss rods are employed to show that p-box models are optimal for modeling random variables to solve numerous practical problems of the probabilistic assessment of reliability of structural elements. The proposed p-box snow load model is based on the Gumbel distribution. The mathematical model used to perform the reliability analysis of planar steel truss elements is proposed. The co-authors provide calculation formulas to assess the reliability of a truss element for different types of p-blocks used to describe random variables depending on the amount of statistical data available. Conclusions. The application of statistically unsubstantiated hypotheses for choosing the probability distribution law or assessing the parameters of the probability distribution of a random variable leads to erroneous assessments of the reliability of structural elements, including trusses. P-boxes ensure a more careful reliability assessment of a structural element, but at the same time this assessment is less informative, as it is presented in the form of an interval. A more accurate reliability interval requires interval-based assessments of distribution parameters or types of p-boxes applied to mathematical models of the limit state, which entails an increase in the economic and labor costs of the statistical data.

Structural Reliability Analysis of Composite Advanced Sail for Virginia Class Submarine

2008 ◽  
Vol 52 (03) ◽  
pp. 165-174
Author(s):  
Christopher D. Eamon ◽  
Masoud Rais-Rohani
Keyword(s):  
Probability Distribution ◽  
Structural Reliability ◽  
Random Variables ◽  
Random Variable ◽  
Computational Effort ◽  
Material Strength ◽  
Reliability Model ◽  
Limit States ◽  
Plane Shear ◽  
Reliability Indices

A structural reliability model is developed for a large composite submarine sail structure. Random variables include material strength and stiffness properties as well as load. Limit states are formulated in terms of material strength parameters and buckling resistance. A series system reliability model that bases structural performance on first component failure is used. A total of 205 random variables and 117 limit states compose the structural system model. Most component reliability indices ranged from 3 to 7, with overall system failure governed by material in-plane shear with a reliability index of 1.84. A probabilistic sensitivity analysis determined that load and material strength were the most significant random variables, while material stiffness parameters were unimportant. Significant computational effort was saved by reducing the number of random variables to the most influential set. The effects of correlation and random variable probability distribution were explored. It was found that correlation has little effect on results, but probability distribution is significant. Recommendations are made to improve performance.

КОКУС ЧОҢДУКТАРДЫН ЫКТЫМАЛДУУЛУКТАРЫН БӨЛҮШТҮРҮҮ ФУНКЦИЯСЫН ОКУТУУНУН ЫКМАЛАРЫ

2020 ◽  
pp. 168-173
Author(s):  
Аалиева Бурул
Keyword(s):  
Distribution Function ◽  
Probability Distribution ◽  
Distribution Density ◽  
Random Variables ◽  
Random Variable ◽  
Continuous Random Variable ◽  
Integral Distribution ◽  
Integral Distribution Function ◽  
Range Of Values

Аннотация: Бөлүштүрүү функциясын, үзгүлтүксүз кокус чоңдуктардын ыктымалдуулуктарын бѳлүштүрүүнүн жиктелиш функциясы (ыктымалдуулуктун тыгыздыгы), ыктымалдуулуктарды бир калыпта бѳлуштүрүү законун аныктоо. Бөлүштүрүү функциясынын касиеттерин окутуу, далилдөө. X кокус чоңдугунун кабыл алууга мүмкүн болгон маанилери (a,b) интервалында жаткандыгынын ыктымалдуулугу бөлүштүрүү функциясынын өсүндүсүнө барабар. Түйүндүү сѳздѳр: Бөлүштурүү функциясы, үзгүлтүксүз кокус чоңдуктардын ыктымалдуулуктары, дискреттик кокус чоңдук, бөлүштүрүүнүн интегралдык функциясы, баштапкы функция. Аннотация: Определять вид непрерывной случайной величины, находить вероятность попадания случайной величины в заданный интервал по заданной функции распределения, уметь находить плотность распределения и равномерное распределения. Еще одно отличие характеристики случайных величин непрерывного действия-включение функции классификации распределения вероятностей, обнаружение первого производного функции последовательности. Следовательно, характеристика распределения вероятностей дискретных случайных величин. Свойства функции распределения обучения и доказательства. Х может быть, чтобы принять параметры диапазона значений (а, б), что функция распределения вероятностей равна приращению. Ключевые слова: Функция распределения, вероятность непрерывной случайной величины, дискретная случайная величина, интегральная функция распределения, первообразная. Annotation: Determine the type of random variable, find the probability of a random variable falling into a given interval by a given distribution function, be able to find the distribution density and uniform distribution. Properties of learning distribution function and evidence. X maybe to take the parameters of the range of values (a, b), that the probability distribution function is equal to the increment. Another difference in the characterization of continuous random variables is the inclusion of the classification function of the probability distribution, the detection of the first derivative of the sequence function. Hence, the characteristic of the probability distribution of discrete random variables Non-decreasing functions, ∫ _ (- ∞) ^ ∞▒ 〖P (x) ax = 1〗. In the case of an individual, if the values of a random variable (a, b) are located within ∫_a ^ b▒ 〖P (x) ax = 1〗 Keywords: Distribution function, probability of continuous random variable, discrete random variable, integral distribution function, antiderivative. DOI: 10.35254/bhu.2019.50.1 ВЕСТНИК БИШКЕКСКОГО ГОСУДАРСТВЕННОГО УНИВЕРСИТЕТА. No4(50) 2019 169 Аннотация: Бөлүштүрүү функциясын, үзгүлтүксүз кокус чоңдуктардын ыктымалдуулуктарын бѳлүштүрүүнүн жиктелиш функциясы (ыктымалдуулуктун тыгыздыгы), ыктымалдуулуктарды бир калыпта бѳлуштүрүү законун аныктоо. Бөлүштүрүү функциясынын касиеттерин окутуу, далилдөө. X кокус чоңдугунун кабыл алууга мүмкүн болгон маанилери (a,b) интервалында жаткандыгынын ыктымалдуулугу бөлүштүрүү функциясынын өсүндүсүнө барабар. X кокус чондугу PP(xx < xx1) ыктымалдуулукта x ден кичине маанилерди кабыл алат; X кокус чондугу xx1 ≤ xx < xx2барабарсыздыктын ыктымалдуулугу PP(xx1 ≤ xx < xx2) түрүндө канааттандырат. Үзгүлтүксүз кокус чоңдуктарды мүнөздөөнүн дагы бир башкача жолу ыктымалдуулукту бөлүштүрүүнүн жиктелиш функциясын киргизүү, тутамдык функциясынын биринчи туундусун табуу. Демек,тутамдык функция жиктелиш функциясынын баштапкы функциясы болорун, дискреттик кокус чондуктардын ыктымалдуулуктарынын бөлүштүрүүсүн мунөздөө. Жиктелиш функциясы кемибөөчү функция, ∫ ff(xx)dddd = 1 ∞ −∞ . Жекече учурда, эгерде кокус чоңдуктардын мүмкүн болгон маанилери (a,b) аралыгында жайгашса, анда � ff(xx)dddd = 1 bb aa Түйүндүү сѳздѳр: Бөлүштурүү функциясы, үзгүлтүксүз кокус чоңдуктардын ыктымалдуулуктары, дискреттик кокус чоңдук, бөлүштүрүүнүн интегралдык функциясы, баштапкы функция. Аннотация: Определять вид непрерывной случайной величины, находить вероятность попадания случайной величины в заданный интервал по заданной функции распределения, уметь находить плотность распределения и равномерное распределения. Еще одно отличие характеристики случайных величин непрерывного действия-включение функции классификации распределения вероятностей, обнаружение первого производного функции последовательности. Следовательно, характеристика распределения вероятностей дискретных случайных величин. Ключевые слова: Функция распределения, вероятность непрерывной случайной величины, дискретная случайная величина, интегральная функция распределения, первообразная. Annotation: Determine the type of random variable, find the probability of a random variable falling into a given interval by a given distribution function, be able to find the distribution density and uniform distribution. Properties of learning distribution function and evidence. X maybe to take the parameters of the range of values (a, b), that the probability distribution function is equal to the increment. Another difference in the characterization of continuous random variables is the inclusion of the classification function of the probability distribution, the detection of the first derivative of the sequence function. Keywords: Distribution function, probability of continuous random variable, discrete random variable, integral distribution function, antiderivative.

scholarly journals ANALYTICAL EVALUATION OF PROCESSING TIME OF A QUERY IN AN INFORMATION SYSTEM

2018 ◽  
pp. 69-73 ◽  
Author(s):  
M. M. Butaev ◽  
A. A. Tarasov
Keyword(s):  
Information Systems ◽  
Normal Distribution ◽  
Processing Time ◽  
Random Variables ◽  
Initial Approximation ◽  
Random Variable ◽  
Sequential Processing ◽  
Processing Times ◽  
Distribution Laws ◽  
Interval Distribution

The normal distribution of a random variable is usually used in studies of the probabilistic characteristics of information systems. However, the approximation by the normal distribution of distributions determined on a limited interval distorts the physical meaning of the model and the numerical results, and it can only be used as an initial approximation. The aim of the work is to improve the methods for calculating the probabilistic characteristics of information systems. The object of the study is an analytical method for calculating the processing time of the query in the system. The subject of the study are formulas for calculating the duration of sequential processing of the query by elements of the system with uniformly distributed random processing times. In deriving the formulas for calculating the probability characteristics of a sum of independent uniformly distributed random variables, the methods of the theory of probability and statistics are applied. It is proposed for random variables, determined only on the positive coordinate axis, to use finite-interval distribution laws, for example, beta distribution. Density formulas and probability functions for sums of two, three and four independent uniformly distributed random variables are derived.

scholarly journals Max Weibull-G Power Series Distributions

2021 ◽  
pp. 15-29
Author(s):  
Munteanu Bogdan Gheorghe
Keyword(s):  
Probability Distribution ◽  
Power Series ◽  
Probability Distributions ◽  
Random Variables ◽  
Random Variable ◽  
Independent Random Variables ◽  
New Family ◽  
The Family ◽  
Distribution Family ◽  
Power Series Distributions

Based on the Weibull-G Power probability distribution family, we have proposed a new family of probability distributions, named by us the Max Weibull-G power series distributions, which may be applied in order to solve some reliability problems. This implies the fact that the Max Weibull-G power series is the distribution of a random variable max (X1 ,X2 ,...XN) where X1 ,X2 ,... are Weibull-G distributed independent random variables and N is a natural random variable the distribution of which belongs to the family of power series distribution. The main characteristics and properties of this distribution are analyzed.

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