Estimates of erosion and sediment delivery have often relied on measurements from locations that were selected to be representative of particular terrain types. Such judgement samples are likely to overestimate or underestimate the mean of the quantity of interest. Probability sampling can eliminate the bias due to sample selection, and it permits the explicit expression of uncertainty with est...

This study examines the efficiency of EPI cluster sampling in assessing the prevalence of diarrhoea and dysentery. A computer was used to simulate fieldwork carried out by a survey taker. The bias and variance of prevalence estimates obtained using EPI cluster sampling were compared with those obtained using simple random sampling and cluster (stratified random) sampling. Efficiency ratios, cal...

Background: Evidence based medicine (EBM) is very crucial in physician’s decisions. Several studies have been conducted on EBM in Iran, but none have referred to barriers regarding EBM. Objectives: In order to address this issue, we conducted a study on physicians to determine their attitudes towards the barriers to EBM. Patients and Methods: This study was a cross-sectional analytical study. O...

BACKGROUND To investigate the prevalence of antibiotic usage in children aged <5 years with acute respiratory tract illness (ARTI) in Iran. MATERIALS AND METHODS Data were collected from a national health survey conducted in 2010 (Iran's Multiple Indicator Demographic and Health Survey). Participants of this cross-sectional study were selected by multistage stratified cluster-random sampling ...

In this research, the covariance estimates were used to estimate population mean in stratified random sampling and combined regression estimates. compared by employing robust variance-covariance matrices with traditional when estimating parameter, through two efficiency criteria (RE) squared error (MSE). We found that significantly improved quality of reducing effect outliers using (MCD, MVE) p...

The common pistachio psylla Agonoscena pistaciae is a key pest of pistachio in Iran. A study was conducted to determine the spatial distribution of psylla nymphs and eggs in a 10 ha pistachio orchard in the Rafsanjan region, southeast of Iran. Three rows, each containing 33 trees (totally 99 trees), were randomly selected in the orchard based on a stratified sampling scheme. In each of the sele...

This study assesses the effectiveness of stratification, based on photo-interpreted forest types, for strategic inventory. It uses results (from stratified sampling) for Total Merchantable Volume (TMV) in 18 Inventory Areas in Tasmanian State forest. The variance of the TMV as determined from stratified sampling is compared with the estimated variance of a simple random sample using the same nu...

this study was conducted based on primary data collected using a questionnaire. a total of 90 respondents among farmers associations were interviewed in kano state of nigeria. therefore, double stage stratified and purposive simple random sampling technique was used to select 30 respondents in each of three (3) farmers associations, one from each of the three (3) agricultural zones of the state...