In the context of auctions for digital goods, an interesting random sampling auction has been proposed by Goldberg et al. [2001]. This auction has been analyzed by Feige et al. [2005], who have shown that it obtains in expectation at least 1/15 fraction of the optimal revenue – which is substantially better than the previously proven constant bounds but still far from the conjectured lower boun...

We propose a new ratio estimator using two auxiliary variables in simple random sampling. We obtain mean square error (MSE) equation of this estimator and theoretically show that our proposed estimator is more efficient than the traditional multivariate ratio estimator under a defined condition. In addition, we support this theoretical result with the aid of a numerical example.

Zhejiang province, China, has implemented a population based, real-time surveillance system that tracks acute cardiovascular diseases (CVDs) events since 2001. This study aimed to describe the system and report CVD incidence, mortality and case-fatality between urban and rural areas in Zhejiang in 2012. The surveillance system employs a stratified random sampling method covering all permanent r...

Background In 2015, more than 1 million refugees arrived in Europe. During their travels, refugees often face harsh conditions, violence and torture in transit countries, but there is a lack of quantitative evidence on their experiences. We present the results of a retrospective survey among refugees in the 'Jungle' of Calais, France, to document their health problems and the violence they endu...

One of the major issues in planning a research is the decision as to how large a sample and the method to be employed to select the estimated sample in order to meet the objective of the research. Sampling is an essential tool for research in medicine. A good number of the medical literature while reporting their sampling method go by stating that the sample was collected by random sampling and...

Background. In many studies, compliance with standard precautions among healthcare workers was reported to be inadequate. Objective. The aim of this study was to assess compliance with standard precautions and associated factors among healthcare workers in northwest Ethiopia. Methods. An institution-based cross-sectional study was conducted from March 01 to April 30, 2014. Simple random samplin...

BACKGROUND All quantifications of mortality, morbidity, and other health measures involve numerous sources of error. The routine quantification of random sampling error makes it easy to forget that other sources of error can and should be quantified. When a quantification does not involve sampling, error is almost never quantified and results are often reported in ways that dramatically oversta...

OBJECTIVE To explore the effect of the educational level of the head of household on the prevalence of malnutrition in Saudi children. METHODS The study was conducted over 2 years in 2004 and 2005 in all regions of the Kingdom of Saudi Arabia (KSA). The design consisted of a stratified multistage probability random sampling of the population of the KSA. The educational level of the heads of t...

urvey research is an important form of scientific inquiry 1 that merits rigorous design and analysis. 2 The aim of a survey is to gather reliable and unbiased data from a representative sample of respondents. 3 Increasingly, investigators administer questionnaires to clinicians about their knowledge, attitudes and practice 2,4,5 to generate or refine research questions and to evaluate the impac...

PURPOSE Based on health care records and trachoma rapid assessments, trachoma was suspected to be endemic in Kaskazini A and Micheweni districts of Zanzibar. This study aimed to investigate the prevalence of trachomatous inflammation-follicular (TF), and trachomatous trichiasis (TT) in each of those districts. METHODS The survey was undertaken in Kaskazini A and Micheweni districts on Unguja ...