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11.
利用《中国工业企业数据库》发布的重工业企业调查数据,基于非参数回归、OLS估计以及Tobit估计的方法研究了控股股东持股比例对企业研发投资强度的影响。研究发现:控股股东持股比例对企业研发投资强度的影响存在门槛效应。股权性质(控股资本类型)、企业年龄对企业研发投资强度的影响并不显著,但企业规模对企业研发投资强度带来显著性影响。文章认为,控股股东持股比例大约保持在50%~80%左右更利于企业技术创新;企业间应加强技术创新合作以形成研发投资的规模效应。 相似文献
12.
This study explored the case of a former addict, focusing on his existential self‐interpretation and identity transformation process. This study began from the question of whether philosophical processes related to existential self‐interpretation could lead to the formation of the concept of bottoming out and of identity transformation. To answer this question, the study analyzed the case of a male in his mid‐forties who was addicted to drugs for approximately 30 years and has only recently maintained abstinence. The study used the phenomenological approach to determine the meaning drugs held for him in each stage, and what drug‐related identity he had in each stage. Further, this study identified the integrative implications of these meanings in terms of existential self‐interpretation and identity transformation. The four different identities the man identified for the four stages of his life were juvenile delinquent, gang member, half‐gangster, and breadwinner, and the associated meanings drugs had for him during each period were “glue,” “filthy,” “leeches,” and “abstinence,” respectively. Finally, this study elucidated the integration of these meanings through the hermeneutic circle, identified the social welfare implications of the findings, and developed educational recommendations. 相似文献
13.
The study of drug synergy plays a prominent role in the search for drug combinations with beneficial interactions. Firstly, in this process, the drug-effect response of individual parts and the mixture needs to be derived. This function is usually well described by Hill (or other logistic or sigmoid) curve. Due to its boundedness, it allows the measured data to be normalized. The normalized data can then be processed by interaction analysis using the Loewe, Bliss, or other models to evaluate possible synergy or antagonism of two or more drugs. However, sometimes, the drug-effect responses observed in pharmaceutical research do not appear to be bounded. Theoretically, the drug-effect curve cannot grow to infinity, but it may be impossible to determine its upper bound within the observed region. In this case, standard models cannot be used, since they assume that data are normalized. The approach of this article bypasses the need to normalize the data, allowing its broader application and usefulness in finding potential synergies in pharmaceutical research. 相似文献
14.
In this paper, Abdelfatah and Mazloum's (2015) two-stage randomized response model is extended to unequal probability sampling and stratified unequal probability sampling, both with and without replacement. The extended models result in more efficient estimators than Lee et al.'s (2014) estimators of the proportion of the population having a sensitive attribute. 相似文献
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16.
This paper applies stratified random sampling using Neyman allocation to Mangat et al. (1992) unrelated question randomized response (RR) strategy for both completely truthful reporting and less than completely truthful reporting. It is shown that, for the prior information given, our new model is more efficient in terms of variance (in the case of completely truthful reporting) and mean square error (in terms of less than completely truthful reporting) than Kim and Elam's (2007) model. Numerical illustrations and graphs are also given in support of the present study. 相似文献
17.
Yoonsuh Jung 《统计学通讯:理论与方法》2017,46(5):2447-2453
By releasing the unbiasedness condition, we often obtain more accurate estimators due to the bias–variance trade-off. In this paper, we propose a class of shrinkage proportion estimators which show improved performance over the sample proportion. We provide the “optimal” amount of shrinkage. The advantage of the proposed estimators is given theoretically as well as explored empirically by simulation studies and real data analyses. 相似文献
18.
This study analyzes three years of data on misdemeanor drug offenders in Winnebago County, Wisconsin. A portion of these offenders opted into a Misdemeanor Drug Diversion Program (MDDP) offered instead of traditional adjudication. Recidivism in the treatment and comparison groups is estimated using standard binary response techniques augmented with propensity score matching to address selection bias. Results show that the MDDP reduces the probability of re-offense by 16%, after adjusting for possible selection bias. Cox proportional hazard modeling is also used to assess time-to-re-offense differentials between the treatment and comparison groups. The survival analysis indicates that the hazard rate of re-offense is 60% lower per day among those treated with the MDDP program than those who did not complete the program. The average number of days to re-offense among those that do re-offend is 297 days in the treatment group and 203 days in the comparison group. 相似文献
19.
The crux of this article is to estimate the mean of the number of persons possessing a rare sensitive attribute based on the Mangat (1991) randomization device by utilizing the Poisson distribution in simple random sampling and stratified sampling. Properties of the proposed randomized response (RR) model have been studied along with recommendations. It is also shown that the proposed model is more efficient than that of Land et al. (2011) in simple random sampling and that of Lee et al. (2013) in stratified random sampling when the proportion of persons possessing a rare unrelated attribute is known. Numerical illustrations are also given in support of the present study. 相似文献
20.
针对传统众数估计值会因为组距的改变而不稳定,在已有的半极差(样本)众数估计方法上,提出多比例极差(样本)众数估计新方法。模拟研究显示,相对于半极差(样本)众数估计方法,该方法估计结果更稳定、准确。在实证分析中,基于2014、2015年国家一体化住户调查数据,使用新方法计算了新疆兵团居民人均可支配收入众数。结果表明,众数可以作为居民人均可支配收入平均数、中位数的有益补充,众数在政府统计中的推广及应用具有一定的可行性与必要性。 相似文献