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Ester Samuel-Cahn 《The American statistician》2013,67(3):156-157
Three sampling designs are considered for estimating the sum of k population means by the sum of the corresponding sample means. These are (a) the optimal design; (b) equal sample sizes from all populations; and (c) sample sizes that render equal variances to all sample means. Designs (b) and (c) are equally inefficient, and may yield a variance up to k times as large as that of (a). Similar results are true when the cost of sampling is introduced, and they depend on the population sampled. 相似文献
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Ester McGeeney 《International Journal of Social Research Methodology》2015,18(3):307-319
This paper examines the temporal and ethical affordances of commercial social media platforms, such as Twitter, as tools for engaging in social research and knowledge exchange. Drawing on activity that took place during the New Frontiers in Qualitative Longitudinal Research seminar series, the article reports on using Twitter and other social media platforms to document, share and archive ‘data’ from a series of research events. It also experiments with new modes of research writing, using fragments of ‘data’ from Twitter to distil research knowledge and ideas, whilst also capturing the pace and form of this live method of social documentation and knowledge exchange. Bringing together conversations within digital sociology about how to ‘do’ time in digital research, with methodological debates among qualitative longitudinal researchers about how to research social and biographical continuity and change, the paper argues that the presentist focus in digital research is far from inevitable. Attending to time in digital media demands that we are alert to questions of authorship, audience and co-production, recognizing the labour of research and the provenance of research knowledge, ‘data’ and ideas. 相似文献
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Ester Carolina Apesoa-Varano 《Qualitative sociology》2016,39(1):27-47
The profession and practice of nursing has been studied from quite diverse scholarly perspectives in the United States and abroad. Feminist critiques focus on the gendering of caring and its knowledge/skill features, while professionalization advocates view emotive caring as secondary to other critical activities necessary for the occupational advancement of nursing. Based on ethnographic observations 30 in-depth, semi-structured interviews with nurses across different units working at a large urban hospital, this paper examines how nurses define caring as knowledge-based, skilled work. Specifically, nurses described four types of skills—observational, analytical, interactional, and comforting—that they deploy in the accomplishment of caring work at the bedside. My findings go beyond previous literature in this area by showing how nurses think of caring work in line with occupational strategies that emphasize their biomedical knowledge and diagnostic skills and uphold an advocacy or intermediary role in health care. I argue that while this ideological work may reassure nurses of their professional identity and critical role in health care, it may also reinforce the dilemma of nurse professionalization by obscuring the organizational nature of caring, as it remains an unsupported dimension of their work. 相似文献
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Ester Samuel-Cahn 《Journal of statistical planning and inference》1983,8(3):347-354
Let Xi be i.i.d. random variables with finite expectations, and θi arbitrary constants, i=1,…,n. Yi=Xi+θi. The expected range of the Y's is Rn(θ1,…,θn)=E(maxYi-minYi. It is shown that the expected range is minimized if and only if θ1=?=θn. In the case where the Xi are independently and symmetrically distributed around the same constant, but not identically distributed, it is shown that θ1=?=θn are not necessarily the only (θ1,...,θn) minimizing Rn. Some lemmas which are applicable to more general problems of minimizing Rn are also given. 相似文献
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