Minimum penalized φ-divergence estimation under model misspecification

This paper focuses on the consequences of assuming a wrong model for multinomial data when using minimum penalized φ-divergence, also known as minimum penalized disparity estimators, to estimate the model parameters. These estimators are shown to converge to a well-defined limit. An application of the results obtained shows that a parametric bootstrap consistently estimates the null distribution of a certain class of test statistics for model misspecification detection. An illustrative application to the accuracy assessment of the thematic quality in a global land cover map is included.Ministerio de Economía y Competitivida

Homogeneity of marginal distributions for a large number of populations

Assume that a random vector is observed in populations and independent samples of that random vector are available at each population. Assume that and have the same dimension. Our purpose is to test the equality of the marginal distributions of and in the populations when is large compared to the sample sizes. With this aim, we propose and study a test statistic that compares the empirical characteristic functions of the marginal distributions. Under the null, the test statistic is asymptotically free-distributed. An expression of the asymptotic power is also derived, which allows to study the consistency of the test. No assumption is made on the distribution of and , which can be continuous, discrete or mixed; moreover, no assumption is made about moments. A simulation study investigates the finite sample performance of the new test. The proposal is applied to study air pollution levels that are directly related to environmental health, in all countries where observations are available

A New Approach to the Quality Control of Slope and Aspect Classes Derived from Digital Elevation Models

The usefulness of the parameters (e.g., slope, aspect) derived from a Digital Elevation Model (DEM) is limited by its accuracy. In this paper, a thematic-like quality control (class-based) of aspect and slope classes is proposed. A product can be compared against a reference dataset, which provides the quality requirements to be achieved, by comparing the product proportions of each class with those of the reference set. If a distance between the product proportions and the reference proportions is smaller than a small enough positive tolerance, which is fixed by the user, it will be considered that the degree of similarity between the product and the reference set is acceptable, and hence that its quality meets the requirements. A formal statistical procedure, based on a hypothesis test, is developed and its performance is analyzed using simulated data. It uses the Hellinger distance between the proportions. The application to the slope and aspect is illustrated using data derived from a 2×2 m DEM (reference) and 5×5 m DEM in Allo (province of Navarra, Spain)

Testing for proportions when data are classified into a large number of groups

When dealing with categorical data, a common concern is to check if the observed relative frequencies agree with a certain fixed vector of ideal proportions. Suppose that the population is divided into subpopulations or groups. In such a case, the ideal proportions could vary among groups and one may be interested in simultaneously testing if the observed proportions agree with those ideal proportions in all groups. A novel procedure is proposed for carrying out such a testing problem. The test statistic is shown to be asymptotically normal, avoiding the use of complicated resampling methods to get -values. The asymptotic behavior of the test under alternatives is also studied. Here, by asymptotic, we mean when the number of groups increases; the sample sizes of the data from each group can either stay bounded or grow with the number of groups. The finite sample performance of the new test is empirically evaluated through an extensive simulation study. The usefulness of the proposal is illustrated with some data sets

Control estricto de matrices de confusión por medio de distribuciones multinomiales

Las matrices de confusión son la forma más usual y estándar de informar sobre la exactitud temática de productos derivados de la clasificación de datos procedentes de imágenes. En este marco, son ampliamente utilizados dos índices: el porcentaje de acuerdo y el índice Kappa. Ambos son índices globales y no permiten un control categoría por categoría y, aún menos, establecer dentro de una categoría condiciones específicas. En este trabajo se propone un método novedoso basado en la distribución multinomial y en un test estadístico exacto. De esta forma, se pueden establecer las preferencias de exactitud para cada categoría y también establecer cierto grado de mala clasificación entre distintas categorías

The Power Muth Distribution

Muth introduced a probability distribution with application in reliability theory. We propose a new model from the Muth law. This paper studies its statistical properties, such as the computation of the moments, computer generation of pseudo-random data and the behavior of the failure rate function, among others. The estimation of parameters is carried out by the method of maximum likelihood and a Monte Carlo simulation study assesses the performance of this method. The practical usefulness of the new model is illustrated by means of two real data sets, showing that it may provide a better fit than other probability distributions

Communication, coordination and competition in the beauty contest game: Eleven classroom experiments

This paper introduces some new features in the standard experimental design of the beauty contest in order to allow communication among participants. With that aim, we use the mode instead of the mean and non-rival payoffs. This design encourages students to communicate their guessed number, with a higher probability if subjects know the 0 Nash equilibrium. The lack of communication can only be explained by subjects endowed with competitive other-regarding preferences. Experiments are run in 11 classrooms ranging from 11 to 60 students in size. Participants are given at least one week to submit their guesses and a questionnaire explaining their choice. Results indicate that: i) communication induces coordination in the responses, ii) communication does not guarantee any improvement in the average reasoning level, iii) there exist significative differences according to classroom size and duration of degree

Teaching Nash Equilibrium and Strategy Dominance: A Classroom Experiment on the Beauty Contest

The aim of this investigation is to show how the use of classroom experiments may be a good pedagogical tool to teach the Nash equilibrium (NE) concept. For our purposes, the basic game is a repeated version of the Beauty Contest Game (BCG), a simple guessing game in which repetition lets students react to other players' choices and converge iteratively to the equilibrium solution. We perform this experiment with undergraduate students with no previous training in game theory. After four rounds, we observe a clear decreasing tendency in the average submitted number in all groups. Thus, our findings prove that by playing a repeated BCG, students quickly learn how to reach the NE solution

RECL 197 - 3-Jul-83

Acute flaccid paralysis (AFP) surveillance is key for global polio eradication. It allows detecting poliovirus (PV) reintroductions from endemic countries. This study describes AFP surveillance in Spain from 1998 to 2015. During this time, 678 AFP cases were reported to the Spanish National Surveillance Network. The mean notification rate was 0.58 AFP cases/100,000 population under 15 years old (range: 0.45/100,000-0.78/100,000). Two periods (P) are described: P1 (1998-2006) with the AFP notification rate ranging from 0.66/100,000 to 0.78/100,000, peaking in 2001 (0.84/100,000); and P2 (2007-2015) when the AFP rate ranged from 0.43/100,000 to 0.57/100,000, with the lowest rate in 2009 (0.31/100,000). No poliomyelitis cases were caused by wild PV infections, although two Sabin-like PVs and one imported vaccine-derived PV-2 were detected. Overall, 23 (3.4%) cases met the hot case definition. Most cases were clinically diagnosed with Guillain-Barré syndrome (76.9%; 504/655). The adequate stool collection rate ranged from 33.3% (7/21) to 72.5% (29/40). The annual proportion of AFP cases with non-polio enterovirus findings varied widely across the study period. AFP surveillance with laboratory testing for non-polio enteroviruses must be maintained and enhanced both to monitor polio eradication and to establish sensitive surveillance for prompt detection of other enteroviruses causing serious symptoms.We sincerely thank Odorina Tello, María Victoria Martínez de Aragón and Gloria Trallero for their valuable contributions to the implementation and development of the National Action Plan Aimed at the Achievement of the Certificate of Polio Eradication, and especially for coordinating the Acute Flaccid Paralysis Surveillance System and the Enterovirus Laboratory Networks in Spain.S