a number of 1810 members of the water user associations (wuas) of jarghouyeh district consisted the statistical population of the study, out of which 150 farmers were selected as sample using proportionate stratified random sampling technique. a questionnaire was developed for gathering the data and information. content validity and cronbach alpha proved both the validity and reliability of the...

A comparison is made between the variance of the estimator of the total of a variable obtained from both a simple and a stratified random sampling, in which the sample sizes of some strata are equal to the stratum population size. It is shown that in this case, the advantage of the stratified sample could depend on the sample size. The paper presents inequalities that determine, as a function o...

BACKGROUND One of the main challenges of healthcare systems of developing countries is health inequality. Health inequality means inequality in individuals' ability and proper functioning, resulting in inequality in social status and living conditions, which thwarts social interventions implemented by the government. OBJECTIVES This study aimed to determine and prioritize the social determina...

We propose a jackknife variance estimator for the population average from two, two-phase samples after imputation. The jackknife method has long been used to estimate and reduce bias, but has now become a valuable tool for variance estimation. We apply two different sampling methods, (simple random sampling and stratified random sampling) to derive jackknife variance estimators for the twosampl...

A stratified random sampling method is preferred for selecting varied populations with outliers. As opposed to plain sampling, increases statistical precision by reducing estimator variance. Before the estimator's variance, stratum boundary identification and data apportionment must be solved. In this study, a Neyman allocation strategy used address determination issue in mixed populations. add...

the purpose of this study was to determine students’ attitudes toward international agricultural issues. the population for the study consisted of agricultural extension students at tehran and shiraz universities, agriculture and natural resources colleges’ (n= 170). a stratified random sampling technique was employed to select samples, (n= 120). the study was conducted during the fall 2007 usi...

The paper presents a model that extends the stochastic finite element method to the modelling of transitional energetic–statistical size effect in unnotched quasibrittle structures of positive geometry (i.e. failing at the start of macro-crack growth), and to the low probability tail of structural strength distribution, important for safe design. For small structures, the model captures the ene...

Reservoir sampling is a well-known technique for random sampling over data streams. In many streaming applications, however, an input stream may be naturally heterogeneous, i.e., composed of substreams whose statistical properties may also vary considerably. For this class of applications, the conventional reservoir sampling technique does not guarantee a statistically sufficient number of tupl...

Sustainability has always been an emphasized topic in policy making and planning the agricultural sector of developing countries. Despite this fact, sustainable agriculture not realized so far because various complex challenges these The lack a structured scientific research on prompted us to conduct study fill gap create useful knowledge issue. In regard, 300 Iranian experts, selected through ...