Full-text resources of CEJSH and other databases are now available in the new Library of Science.
Visit https://bibliotekanauki.pl

Results found: 7

first rewind previous Page / 1 next fast forward last

Search results

Search:
in the keywords:  skewness
help Sort By:

help Limit search:
first rewind previous Page / 1 next fast forward last
1
Publication available in full text mode
Content available

Confidence Intervals for The Ratio of Two Means Using the Distribution of the Quotient of Two Normals

100%
Galeone C., Pollastri A.
Statistics in Transition new series
|
2012
|
vol. 13
|
issue 3
451-472
EN
In various scientific fields such as medicine, biology and bioassay, several ratio quantities assumed to be Normal, are of potential interest. The estimator of the ratio of two means is a ratio of two random variables normally or asymptotically normally distributed. The present paper shows the importance of considering the real distribution of the estimator of the ratio of two means, because generally the approximation to Normal is not satisfied. The estimated asymptotic cumulative and density function of the estimator of the ratio is presented, with several considerations on the skewness. Finally, a new method for building confidence intervals for the ratio of two means was proposed. In contrast to other parametric methods, this new method is worthy to be preferred because it considers the skewness in the distribution of the ratio estimator, and the confidence intervals are always bounded.
2
Publication available in full text mode
Content available

The detectability of asymmetric distributions deviating from normality due to small skewness

100%
Sulewski P.
Przegląd Statystyczny
|
2023
|
vol. 70
|
issue 1
13-53
EN
The aim of this article is to test the ability of goodness-of-fit tests (GoFTs) to detect any deviations from normality. A very specific case is considered, namely the deviation from normality consisting in the coincidence of asymmetry and small γ1 skewness. The first step in achieving the aforementioned aim is to compile a set of normality-oriented GoFTs commonly recommended for use, as described in the recently published literature. The second step is to create a family of asymmetric distributions with a non-constant γ1, further referred to as alternatives. The formulas for calculating γ1 are provided for each alternative. To compare the alternatives with the normal distribution, a relevant similarity measure is applied. The third step involves running a Monte Carlo simulation. The study investigates 21 GoFTs and 13 alternatives. The obtained results show that the LFα,β and Hn GoFTs prove most effective in detecting asymmetric distributions that deviate from normality due to small skewness, equal to even 0.05.
3
Publication available in full text mode
Content available

Skew-normal Distribution - Basic Properties and Areas of Applications

100%
Jadamus-Hacura M., The Karol Adamiecki University of Economics K.
Acta Universitatis Lodziensis. Folia Oeconomica
|
2006
|
vol. 196
EN
The skew-normal is a class of distribution that includes the normal distribution as a special case. A systematic treatment of the skew-normal distribution has been given in Azzalini (1985, 1986); generalizations to the multivariate case are given in Azzalini and Capitanio (1999), while Azzalini and Capitanio (2003) propose a further extension with a skew-t distribution. In this paper we study the properties of this class of density functions and we investigate the applicability of this distributions for modeling some financial and income data.
PL
Klasa skośnych rozkładów normalnych zawiera jako szczególny przypadek rozkład normalny. Szczegółowemu omówieniu własności rozkładu skośnego normalnego poświęcona jest praca Azzalini (1985, 1986); przypadek wielowymiarowy przedstawili Azzalini i Capitanio (1999), natomiast w pracy tych autorów z roku 2003 można znaleźć dalsze rozszerzenie tej klasy rozkładów o rozkłady skośne t-Studenta. W niniejszym artykule przedstawiono podstawowe własności funkcji gęstości omawianych rozkładów i pokazano możliwości ich wykorzystania w modelowaniu dochodów i danych finansowych.
4
Publication available in full text mode
Content available

Wpływ szoków naftowych na asymetrię cyklu koniunkturalnego - analiza przełącznikowych modeli Markowa dla państw Unii Europejskiej

88%
Geise A.
Zeszyty Naukowe PWSZ w Płocku. Nauki Ekonomiczne
|
2015
|
vol. 2(22)
411-420
EN
In the study the Markov-switching models with oil prices to analysis of business cycle asymmetries were considered. We find evidence that business cycles in 1995-2014 were asymmetric in France, Denmark, Poland, Czech Republic and European Union.
5
Publication available in full text mode
Content available

SKOŚNOŚĆ ROZKŁADU A ESTYMACJA KWANTYLOWYCH MIAR RYZYKA – PRZYPADEK RYNKU METALI

63%
Krężołek D.
Metody Ilościowe w Badaniach Ekonomicznych
|
2017
|
vol. 18
|
issue 4
624-634
PL
Pomiar ryzyka inwestycyjnego wymaga zastosowania narzędzi, które w odpowiedni sposób uwzględniają anomalie obserwowane w empirycznych rozkładach stóp zwrotu. Klasyczne modele szacowania ryzyka zakładają gaussowskie rozkłady prawdopodobieństwa, które nie uwzględniają asymetrii rozkładu, mającej związek z występowaniem obserwacji ekstremalnych. Takie obserwacje istotnie wpływają na poziom prawdopodobieństwa w ogonach rozkładów. W pracy podjęto próbę oceny wpływu skośności rozkładu prawdopodobieństwa na ocenę poziomu ryzyka inwestycji podejmowanych na rynku metali. Zastosowano kwantylowe miary ryzyka, m.in. wartość zagrożoną oraz warunkową wartość zagrożoną przy wykorzystaniu różnych teoretycznych rozkładów prawdopodobieństwa. Analizę przeprowadzono uwzględniając okres kryzysu finansowego.
EN
Investment risk measurement requires specific statistical tools which take into account anomalies observed in empirical distributions of returns. Classical models used for modelling risk are based on gaussian approach and do not include asymmetry in data, which is significantly related to extreme observations. These observations affect the thickness of both right and left tails of the empirical distributions. In this paper the influence of skewness observed in empirical probability distributions on the assessment of extreme risk is examined. The area of research is the metals market within the period including economic crisis. The analysis contains some selected quantile risk measures and their estimation using chosen theoretical distributions. Keywords: skewness, risk measurement, Value-at-Risk, extreme risk, heavy tails
6
Publication available in full text mode
Content available

An approach to measuring the relation between risk and return. Bayesian analysis for WIG data

63%
Pipień M.
Folia Oeconomica Cracoviensia
|
2007
|
vol. 48
95-117
EN
The main goal of this paper is an application of Bayesian inference in testing the relation between risk and return of the financial time series. On the basis of the Intertemporal CAl’M model, proposed by Merton (1973), we built a general sampling model suitable in analysing such relationship. The most important feature of our model assumptions is that the possible skewness of conditional distribution of returns is used as an alternative source of relation between risk and return. Thus, pure statistical feature of the sampling model is equipped with economic interpretation. This general specification relates to GARCH-In-Mean model proposed by Osiewalski and Pipień (2000). In order to make conditional distribution of financial returns skewed we considered a constructive approach based on the inverse probability integral transformation. In particular, we apply the hidden truncation mechanism, two approaches based on the inverse scale factors in the positive and the negative orthant, order statistics concept, Beta distribution transformation, Bernstein density transformation and the method recently proposed by Ferreira and Steel (2006). Based on the daily excess returns of WIG index we checked the total impact of conditional skewness assumption on the relation between return and risk on the Warsaw Stock Market. Posterior inference about skewness mechanisms confirmed positive and decisively significant relationship between expected return and risk. The greatest data support, as measured by the posterior probability value, receives model with conditional skewness based on the Beta distribution transform ation with two free parameters.
7
Publication available in full text mode
Content available

Parametry portfela zawierającego inwestycje alternatywne

63%
Kasprzak-Czelej A.
Annales Universitatis Mariae Curie-Skłodowska, sectio H – Oeconomia
|
2013
|
vol. 47
|
issue 3
EN
The article briefly describes the portfolio characteristics connected with the distribution of its rates of return and presents the results of empirical studies on the parameters of portfolios including particular alternative investments (commodities, precious metals, real estate fund, hedge funds, investable wine).
PL
Artykuł nie zawiera abstraktu w języku polskim
first rewind previous Page / 1 next fast forward last
JavaScript is turned off in your web browser. Turn it on to take full advantage of this site, then refresh the page.