Search results for "Cluster sampling"
showing 10 items of 11 documents
Caries prevalence in children from Valencia (Spain) using ICDAS II criteria, 2010
2014
Objectives: To assess the oral health status of the child population and its evolution over the 2004-2010 period. Study Design: A descriptive cross-sectional study of the entire schoolchild population of the Valencia region of Spain was conducted using cluster sampling. Seventy schools were selected. The sample size was 1373 pupils, aged 6, 12 and 15 years. The children were examined in November and December 2010, at their schools, by 6 examiners calibrated in the ICDAS II method. The descriptive statistics, comparison of means and comparison of proportions (p0) was 30% in primary dentition at 6 years and 37.7% and 43.6% in permanent dentition at 12 and 15 years respectively. At 6, 12 and 1…
Influence of lifestyle on oral health behavior among rural residents of Udaipur district, India
2010
Objectives: To determine the relation of life style with dental health behavior such as tooth brushing frequency, use of extra cleansing devices and regular visits to dentist among rural residents of Udaipur district, India. Study design: The study population comprised of 1001 rural population between the ages 18 to 69 years selected by multi stage stratified cluster sampling procedure. Personal interviews were conducted by three trained interviewers who collected information on socio-demographic and lifestyle factors in addition to some aspects of dental health behavior including tooth brushing frequency, use of extra cleaning devices like dental floss and regular visits to dentist. Result…
Caries Prevalence Evolution and Risk Factors among Schoolchildren and Adolescents from Valencia (Spain): Trends 1998–2018
2020
The aim of this study was to determine the caries status and risk factors in the schoolchildren of Spain&rsquo
Health-related quality of life and pain in children and adolescents: A school survey
2016
Background Pain problems are common in children and adolescents. Measures of health-related quality of life (HRQoL) can be used to assess children’s subjective perspectives of pain experience and its impact on their life. The aims of the study were to describe HRQoL and the prevalence of pain in a nonclinical population of children and adolescents, and to analyze the relationships between HRQoL, pain, sex, and age in a sample of children and adolescents aged 8–18 years. Methods This cross-sectional study involved a cluster sample of 20 randomly selected schools drawn within a region of Norway. The final study sample included 1099 children and adolescents. We measured HRQoL using the generic…
The status of dental caries and related factors in a sample of Iranian adolescents.
2010
Objective: To describe the status of dental caries in a sample of Iranian adolescents aged 14 to 18 years in Qazvin, and to identify caries-related factors affecting this group. Study design: Qazvin was divided into three zones according to socio-economic status. The sampling procedure used was a stratified cluster sampling technique; incorporating 3 stratified zones, for each of which a cluster of school children were recruited from randomly selected high schools. The adolescents agreed to participate in the study and to complete a questionnaire. Dental caries status was assessed in terms of decayed teeth (DT), filled teeth (FT) and decayed, missing and filled teeth (DMFT). A multivariate …
Horvitz-Thompson estimators for functional data: asymptotic confidence bands and optimal allocation for stratified sampling
2009
When dealing with very large datasets of functional data, survey sampling approaches are useful in order to obtain estimators of simple functional quantities, without being obliged to store all the data. We propose here a Horvitz--Thompson estimator of the mean trajectory. In the context of a superpopulation framework, we prove under mild regularity conditions that we obtain uniformly consistent estimators of the mean function and of its variance function. With additional assumptions on the sampling design we state a functional Central Limit Theorem and deduce asymptotic confidence bands. Stratified sampling is studied in detail, and we also obtain a functional version of the usual optimal …
A Bayesian comparison of cluster, strata, and random samples
1999
When sampling from finite populations, simple random sampling (SRS) is rarely used in practice, due to either high cost or information to be gained from more efficient designs. Bayesian hierarchical models are a natural framework to model the non-randomness in the sample. This paper concentrates on the effects that the design has on inference about characteristics of the finite population, and makes a critical comparison among some common designs.
Analysis of Educational Frequency Data from a Complex Sample Survey
1991
Abstract Some recent methods are presented for analyzing categorial data from complex surveys involving clustering familiar in educational research where e.g. teaching groups are used as sample clusters. The methods are introduced through a discussion of the test of independence on a two‐way table and the analysis of a two‐way table using logistic regression models. The analyses are illustrated using data from the First National Assessment of the Finnish Comprehensive School 1979. The primary focus of the paper is on the methods that provide first‐order corrections to standard multinomial‐based chi‐square tests by taking account of survey design effects. Both first‐ and second‐order correct…
Emotional and behavioral difficulties in adolescence: Relationship with emotional well-being, affect, and academic performance
2018
Abstract The main purpose of this study was to examine difficulties in behavioral and emotional adjustment and their relationship to subjective well-being, positive and negative affect, and academic performance in a representative sample of nonclinical adolescents. The sample consisted of a total of 1,664 participants (M = 16.12 years, SD = 1.36, range 14-19 years), selected through stratified cluster sampling. The instruments used were the Strengths and Difficulties Questionnaire (SDQ), the Positive and Negative Affect Schedule for Children (PANAS-C), the Personal Wellbeing Index-School Children (PWI-SC), the ad hoc academic performance questionnaire, and the Oviedo Scale of Response Infre…
Need for Orthodontic Treatment in Pupils Aged between 12 and 15 in the Valencian Region (Spain)
2021
The World Health Organization recommends carrying out periodic epidemiological studies in order to provide a basis for the evaluation of the state of health of the population at any given time