Population stratification (PS) is referred to the systematic difference in allele frequencies between subpopulations in a population. It could cause a false-positive conclusion in a case-control association study, where the association is due to the structure of the underlying population, not a disease-associated locus. In this paper, we study the joint effects of PS and data sampling when the ...

this study aimed to investigate the relationship between job satisfaction and rganizational citizenship behavior and personality traits city staff lorestan. the research objective of the application and the method of data collection, descriptive, correlative to-be conducted in 1394. the study population of 500 municipal employees lorestan 217 employees were selected using cochran formula the se...

this research aims to design the portfolio entrepreneurship model and to analyze the effect of social capital, prior experience and knowledge, the entrepreneur’s financial resources, as well as human capital on portfolio entrepreneurship and also to investigate the effect of portfolio entrepreneurship on recognition of new opportunities, as well as business growth and development. the research ...

The application of ranked set sampling (RSS) techniques to data from a dichotomous population is currently an active research topic, and it has been shown that balanced RSS leads to improvement in precision over simple random sampling (SRS) for estimation of a population proportion. Balanced RSS, however, is not in general optimal in terms of variance reduction for this setting. The objective o...

An almost unbiased estimator using known value of some population parameter(s) is proposed. Under simple random sampling without replacement (SRSWOR) scheme the expressions for bias and mean square error (MSE) are derived. Numerical illustrations are given.