Search results for "STATISTICS"
showing 10 items of 7671 documents
An appraisal of the fit of a cognitive behavioural model of headache in University students
2018
The aim of this study was to evaluate the fit of a cognitive behavioural model of headache in the population of University students, from Córdoba,Argentina. The direct and indirect contributions to pain intensity of control beliefs, beliefs and thoughts about pain and coping strategies weredetermined, as were the direct contributions of pain behaviours and disability. The sample was comprised of 382 students of both genders fromseveral Universities. Multiple instruments were administered to measure the variables proposed in the cognitive behavioural model of headachefollowed by a descriptive and exploratory analysis of the data. Structural equation modelling was used and revealed an accepta…
Age-Structured Human Population Dynamics
2006
ABSTRACT A von Foerster-McKendrick model to study age-structured human population dynamics is presented in this paper. Forecasts of population density (population per age unit) depending on ages are possible using this model. The model consists of a quasi-linear first order partial differential equation for the dynamics of population density per age-unit (except for the zero-age), a boundary condition for the births flow at zero-age, and an initial condition for the population density at the initial instant. A general solution independent of the particular human-system under study is obtained based on some hypotheses about the mathematical structure of its input variables. The model has bee…
Natural induction: An objective bayesian approach
2009
The statistical analysis of a sample taken from a finite population is a classic problem for which no generally accepted objective Bayesian results seem to exist. Bayesian solutions to this problem may be very sensitive to the choice of the prior, and there is no consensus as to the appropriate prior to use.
Individual consistency and sex differences in migration strategies of Scopoli’s shearwaters Calonectris diomedea despite year differences
2014
Abstract Recently-developed capabilities for tracking the movements of individual birds over the course of a year or longer has provided increasing evidence for consistent individual differences in migration schedules and destinations. This raises questions about the relative importance of individual consistency versus flexibility in the evolution of migration strategies, and has implications for the ability of populations to respond to climatic change. Using geolocators, we tracked the migrations of Scopoli’s shearwaters Calonectris diomedea breeding in Linosa (Italy) across three years, and analysed timing and spatial aspects of their movements. Birds showed remarkable variation in their …
PEMODELAN GEOGRAPHICALLY WEIGHTED REGRESSION (GWR) PADA PERSENTASE KRIMINALITAS DI PROVINSI JAWA TIMUR TAHUN 2017
2020
Crime is everything that exists in Indonesia. Based on BPS data in 2018, East Java Province ranks first in the Province of North Sumatra and the Special Capital Region of Jakarta. This research was conducted to determine the factors that support crime in each Regency / City of East Java Province. The method used in this research is Weighted Geographic Regression (GWR). Geographically Weighted Regression (GWR) is one of the statistical methods used to model variable responses with regional or area-based predictor variables. Based on the GWR results, it is recognized as a variable Population Density Percentage (X1), Open Unemployment Rate (X2), Poor Population (X3), Population who are Victims…
Modeling of female human body shapes for apparel design based on cross mean sets
2014
This paper is concerned with a method to build prototypes of human bodies that can be used for apparel design. One of the most important issues in the apparel development process is to define a sizing system to provide a good fitting for the majority of the population. Since anthropometric measures do not present the same linear growth with size in each dimension, it is very important to find a prototype that represents as accurately as possible each class in the sizing system. In this paper we propose a method based on the concept of random compact mean set to define prototypes in apparel design. From a cloud of 3D points obtained with a 3D scanner a solid that represents the human body is…
Bayesian Hierarchical Models for Random Routes in Finite Populations
1996
In many practical situations involving sampling from finite populations, it is not possible (or it is prohibitely expensive) to access, or to even produce, a listing of all of the units in the population. In these situations, inferences can not be based on random samples from the population. Random routes are widely used procedures to collect data in absence of well defined sampling frames, and they usually have either been improperly analyzed as random samples, or entirely ignored as useless. We present here a Bayesian analysis of random routes that incorporates the information provided but carefully takes into account the non- randomness in the selection of the units.
On sampling error in evolutionary algorithms
2021
The initial population in evolutionary algorithms (EAs) should form a representative sample of all possible solutions (the search space). While large populations accurately approximate the distribution of possible solutions, small populations tend to incorporate a sampling error. A low sampling error at initialization is necessary (but not sufficient) for a reliable search since a low sampling error reduces the overall random variations in a random sample. For this reason, we have recently presented a model to determine a minimum initial population size so that the sampling error is lower than a threshold, given a confidence level. Our model allows practitioners of, for example, genetic pro…
Herramientas estadísticas para resolver contrastes de hipótesis con contenido biológico: su uso en ecología del siglo XXI
2008
Amenudo la formación que han recibido durante la carrera los jóvenes investigadores tiene notables carencias en los aspectos prácticos de diseño experimental, análisis de datos e interpretación de resultados, lo cual limita de manera decisiva el provecho científico futuro de sus actividades. Eso es especialmente cierto en nuestros días, ya que vivimos una revolución importante en el campo de la metodología estadística e incluso en el procedimiento de hacer inferencia (el salto matemático desde las propiedades de nuestra muestra de datos a las de los parámetros desconocidos de la población, nuestro objeto de estudio), que afecta no sólo a los ecólogos sino a muchas otras disciplinas científi…
Providing insights into browntail moth local outbreaks by combining life table data and semi-parametric statistics
2011
1. Life table studies have been an essential tool for the comprehension of insect population dynamics, although their use has been methodologically biased by a primary focus on mortality factors, especially natural enemies. Thus, studies in natural populations may relegate important mortality sources to the ‘unknown’ or ‘residual’ mortality categories. To overcome this limitation, life tables may be complemented by combining them with other approaches. 2. The aim of the present study was to provide insights into browntail moth Euproctis chrysorrhoea L. (Lepidoptera: Lymantriidae) local outbreaks by combining life table data and statistical modelling. First, E. chrysorrhoea population densit…