Search results for " Sampling"
showing 10 items of 375 documents
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.
Intra-urban residential differentiation in the post-Soviet city: the case of Riga, Latvia
2014
Cities in many Central and Eastern European (CEE) countries have transformed rapidly since the political and socio-economic restructuring started in the early 1990s. Economi reforms, growing income inequalities, changes in housing system and selective residential mobility are resulting in increasing socio-spatial differentiation among urban neighbourhoods also in Riga. In addition, litt le is known about the ethnic dimension of intra-urban residential differentiation, despite the existence of sizeable minority populations. The focus on ethnicity is important, since Riga is the only capital city in the Baltic States where the ethnic majority is outnumbered by the non-Latvian minority. This p…
The Tax Justice Network-Africa v Cabinet Secretary for National Treasury & 2 Others: A Big Win for Tax Justice Activism?
2019
This paper develops an optimization model for selecting a large subsample that improves the representativeness of a simple random sample previously obtained from a population larger than the population of interest. The problem formulation involves convex mixed-integer nonlinear programming (convex MINLP) and is therefore NP-hard. However, the solution is found by maximizing the “constant of proportionality” – in other words, maximizing the size of the subsample taken from a stratified random sample with proportional allocation – and restricting it to a p-value high enough to achieve a good fit to the population of interest using Pearson’s chi-square goodness-of-fit test. The beauty of the m…
Experiencias psicóticas atenuadas y consumo de cannabis en adolescentes de la población general
2019
El propósito de este estudio fue analizar la relación entre las experiencias psicóticas atenuadas y el consumo de cannabis en una muestra representativa de adolescentes de la población general. Un total de 1,588 estudiantes (M=16,13 años; DT = 1,36), 739 eran hombres (46,5%), pertenecientes a 34 escuelas y 98 aulas, seleccionados mediante muestreo aleatorio estratificado por conglomerados, fueron encuestados. Los instrumentos administrados fueron el Cuestionario de Pródromos de Psicosis-Breve, el Cuestionario de Capacidades y Dificultades, el Cuestionario de Consumo de Sustancias Modificado, el Penn Matrix Reasoning Test (PMRT), la Family Affluence Scale-II y la Escala Oviedo de Infrecuenci…
Temporal Distribution of Gastropods In Rocky Intertidal Area In North Manokwari, West Papua
2019
Gastropods is an important organism that commonly found inhabiting the rocky intertidal area. Distribution pattern of this species is influenced by various factors such as population history, microhabitat, predation and a complex interactions between oceanographic dynamics and ecological features. This study aims to compare the temporal distribution pattern of gastropods at two different rocky intertidal area. This research was conducted at the rocky intertidal area of Amban and Nuni, North Manokwari District, West Papua. Data collection was performed during the daylight and night in April and June 2012 using systematic sampling method. The results showed that both physical and chemical fac…
Success in reaching affect self-regulation goals through everyday music listening
2023
While music listening on mobile phones can serve many affect-regulatory goals, success in reaching these goals is yet to be empirically assessed. This study aimed to determine how frequently listeners successfully reach their affect-regulatory goals, and the predictors of this success. Data were collected using the experience sampling app MuPsych, from 293 Finnish participants. Goals were successfully reached in less than half of cases, with adults more successful than adolescents. Success was determined largely within contexts, and strongly predicted by an initial low-valenced emotional state of the listener, suggesting that music listening is particularly useful for those in negative stat…
The fumarolic CO2 output from Pico do Fogo volcano (Cape Verde)
2020
The Pico do Fogo volcano, in the Cape Verde Archipelago off the western coasts of Africa, has been the most active volcano in the Macaronesia region in the Central Atlantic, with at least 27 eruptions during the last 500 years. Between eruptions fumarolic activity has been persisting in its summit crater, but limited information exists for the chemistry and output of these gas emissions. Here, we use the results acquired during a field survey in February 2019 to quantify the quiescent summit fumaroles' volatile output for the first time. By combining measurements of the fumarole compositions (using both a portable Multi-GAS and direct sampling of the hottest fumarole) and of the SO2 flux (u…
Effects of menu structure and touch screen scrolling style on the variability of glance durations during in-vehicle visual search tasks.
2011
The effects of alternative navigation device display features on drivers' visual sampling efficiency while searching forpoints of interest were studied in two driving simulation experiments with 40 participants. Given that the number of display items was sufficient, display features that facilitate resumption of visual search following interruptions were expected to lead to more consistent in-vehicle glance durations. As predicted, compared with a grid-style menu, searching information in a list-style menu while driving led to smaller variance in durations of in-vehicle glances, in particular with nine item displays. Kinetic touch screen scrolling induced a greater number of very short in-v…
The role of daily autonomous and controlled educational goals in students’ academic emotion states: An experience sampling method approach
2018
The present study examines antecedents of university students' academic emotions (Pekrun, Goetz, Titz, & Perry, 2002) in the context of self-determination theory (SDT; Deci & Ryan, 1985; 2000), using realtime assessment and intra-individual analyses. We investigated whether daily autonomous and controlled-motivated educational goals predicted students' academic emotions. University students (N = 55) completed smartphone diaries over 14 consecutive days. The two-week intensive longitudinal data were organized in a hierarchical three-level structure, with situations (Level 1) nested within days (Level 2) nested within students (Level 3). Students' goal motivation was assessed in morning quest…
Occurrence of pharmaceuticals in municipal wastewater treatment plants and receiving surface waters in Central and Southern Finland
2016
The presence of five selected pharmaceuticals, four anti-inflammatory drugs, diclofenac, ibuprofen, ketoprofen, naproxen, and an antiepileptic drug carbamazepine, was determined at four municipal wastewater treatment plants (WWTPs) and in the receiving waterway near the city of Jyväskylä, in central Finland and also in the River Vantaa. First, an analytical method was developed including a pretreatment and purification followed by liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) in the multiple reaction monitoring mode. The studied pharmaceuticals were detected from influents and effluents of four municipal WWTPs and from surface water of eight locations along the water …