The spatio-temporal variogram is an important factor in spatio-temporal prediction through
kriging, especially in fields such as environmental sustainability or climate change, where …

Let Z (s)=(Z 1 (s),…, Z p (s)) t be an isotropic second-order stationary multivariate spatial
process. We measure the statistical association between the p random components of Z with …

In this paper, we obtain a saddlepoint approximation for the small sample distribution of
several variogram estimators such as the classical Matheron's estimator, some M-estimators …

The small sample distribution of the trimmed mean is usually approximated by a Student'st
distribution. But this approximation is valid only when the observations come from a …

Many test statistics follow a χ 2 distribution because a normal model is assumed as
underlying distribution. In this paper we obtain good analytic approximations for the p-value …

In this paper we obtain a linear approximation to the power function of a test that is very
accurate for small sample sizes. This is especially useful for robust tests where not many …

A new way of computing the Tail Area Influence Function (TAIF) exactly is proposed and a
new finite sample robustness measure, based on the TAIF, is introduced. The main …

La mayoría de los Métodos Estadísticos habitualmente utilizados, requieren de unas
suposiciones, como la normalidad de los datos, la cual habitualmente no se tiene y, lo que …

The t-distribution is a very usual distribution for several test statistics because a normal
distribution is frequently assumed as underlying model. Even in some tests based on robust …

Abstract The F (a, b)-distribution is very frequently used in Statistics to compute significance
levels when the individual observations follow a normal distribution. In this paper, we obtain …