et la mesure d’aplatissement de la distribution, le kurtosis: Le coefficient de corrélation linéaire ou coefficient de Pearson r est une mesure du degré auquel. climat à été très chaud coefficient de viscosité climat à été très chaud coefficient d’aplatissement → coefficient d’efficacité → coefficient. On peut augmenter le coefficient d’aplatissement (kurtosis) par un mouvement de Ces relations d’ordre imposent des formes de croissance sur les graphiques.

Author: Dusar Motilar
Country: Panama
Language: English (Spanish)
Genre: Career
Published (Last): 22 June 2004
Pages: 490
PDF File Size: 19.83 Mb
ePub File Size: 9.37 Mb
ISBN: 535-6-87706-278-4
Downloads: 63178
Price: Free* [*Free Regsitration Required]
Uploader: Dailar

Mean arithmetic geometric harmonic Median Mode. Fundamental Statistics for Social Research.

Retrieved from ” https: Mais les apparences sont trompeuses: The comparatively fatter tails of the leptokurtic densities are illustrated in the second image, which plots the natural logarithm of the Pearson type VII densities: Sampling stratified cluster Standard error Opinion poll Questionnaire. The kurtosis can now be seen to be a measure of the dispersion of Z 2 around its expectation.

Depending on the particular measure of kurtosis that is used, there are various interpretations of kurtosis, and of how particular measures should be interpreted. Z -test normal Student’s t -test F -test. All densities in this family are symmetric.

The sample kurtosis is a useful dd of whether there is a problem with outliers in a data set. Journal of Fluid Mechanics.

Kurtosis – Wikipedia

For a bivariate normal distribution, the cokurtosis tensor has off-diagonal terms that are neither 0 nor 3 in general, so attempting to “correct” for an excess becomes confusing.

En ce qui concerne les AVPP, la moyenne nationale est de Population rurale et taux de personnes de 65 ans et plus dans les trois provinces. Larger kurtosis indicates a more serious outlier problem, and may lead the researcher to choose alternative statistical methods. On calcule ensuite des moyennes par commune. De nombreux doutes voir par ex. All this is the price of ‘development’. The images on the right show curves for the following seven densities, on a linear aplatissenent and logarithmic scale:.


In a similar way to the concept of skewnesskurtosis is a descriptor of the shape of a probability distribution and, just as for skewness, there are different ways of quantifying it for a theoretical distribution and corresponding ways of estimating it from a sample from a population.

Views Read Edit View history. Then the mean and skewness exist and are both identically zero. Given a sub-set of samples palatissement a population, the sample excess kurtosis above is a biased estimator of the population excess kurtosis.

On voit en outre sur la carte Fig. For a sample of n values the sample excess kurtosis is.

Such distributions are sometimes termed super-Gaussian. This section needs expansion. Kurtosis is the average or expected value of the standardized data raised to the fourth power. For example, suppose the data values are 0, 3, 4, 1, 2, 3, 0, 2, aplatjssement, 3, 2, 0, 2, 2, 3, 2, 5, 2, 3, The reason not to subtract off 3 is that the bare fourth moment better generalizes to multivariate distributionsespecially when independence is not assumed.

Coefficidnt effects of kurtosis are illustrated using a parametric family of distributions whose kurtosis can be adjusted while their lower-order moments and cumulants remain constant. A distribution with negative excess kurtosis is called platykurticor platykurtotic. D’Agostino’s K-squared test is a goodness-of-fit normality test based on a combination of the sample skewness and sample kurtosis, as is the Jarque—Bera test for normality.


Distributions with kurtosis greater than 3 are said to be aplayissement. Van Oyen et coll. Il n’y a pas de registre ni de connaissance certaine de ses agents.

1. Introduction.

La dispersion des points est assez grande Fig. The only data values observed or observable that contribute to kurtosis in any meaningful way are those outside the region of the peak; i.

Le ceofficient front de mer de Puerto Montt. Ce qui peut aplatidsement la sur-correction. Wikiversity has learning resources about Kurtosis.

For non-normal samples, the variance of the sample variance depends on the kurtosis; for details, please see variance. Wikimedia Commons has media related to Kurtosis.

Then the only free parameter is mwhich controls the fourth moment and cumulant and hence the kurtosis. Category Portal Commons WikiProject. This behavior, termed kurtosis convergencecan be used to detect image splicing in forensic analysis. Such distributions are sometimes termed sub-Gaussian.

The standard measure of kurtosis, originating with Karl Pearsonis based on a scaled version zplatissement the fourth moment of the data or population. Mais l’explication ponctuelle nous laisse insatisfaits et le fatalisme n’a pas encore? En ce qui concerne les soins de premier niveau: A reason why some authors favor the excess kurtosis is that cumulants are extensive.

Leur distribution rappelle dans l’ensemble le mode de colonisation historique Fig. The kurtosis is bounded below by the squared skewness plus 1: