排序方式: 共有119条查询结果,搜索用时 609 毫秒
101.
Ibrahim Hassan Ibrahim 《统计学通讯:理论与方法》2013,42(9):2919-2931
In this paper we evaluate the power of the Mann-Whitney test in the shift model G(x) = F (x+θ) for all x , where the distribution of G is obtained by shifting F by an amount of θ. The bootstrap method was used to evaluate the power of the Mann-Whitney test . A comparison among the bootstrap power , the asymptotic power of the Mann-Whitney test and the t-test power proved that the bootstrap is a better technique , because , it does not require the assumption of normality. 相似文献
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Hassan S. Bakouch 《Journal of applied statistics》2012,39(10):2300-2301
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Miroslav M. Ristić Hassan S. Bakouch Aleksandar S. Nastić 《Journal of statistical planning and inference》2009
A new stationary first-order integer-valued autoregressive process with geometric marginal distributions is introduced based on negative binomial thinning. Some properties of the process are established. Estimators of the parameters of the process are obtained using the methods of conditional least squares, Yule–Walker and maximum likelihood. Also, the asymptotic properties of the estimators are derived involving their distributions. Some numerical results of the estimators are presented with a discussion to the obtained results. Real data are used and a possible application is discussed. 相似文献
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Stephen J. Robson Hassan Vally Abdel-Latif Mohamed Maggie Yu Elizabeth M. Westrupp 《Women and birth : journal of the Australian College of Midwives》2017,30(6):506-510
Background
The proportion of babies born by caesarean section in Australia has almost doubled over the last 25 years. Factors known to contribute to caesarean such as higher maternal age, mothers being overweight or obese, or having had a previous caesarean do not completely account for the increased rate and it is clear that other influences exist.Aim
To identify previously unsuspected risk factors associated with caesarean using nationally-representative data from the Longitudinal Study of Australian Children.Methods
Data were from the birth cohort, a long-term prospective study of approximately 5000 children that includes richly-detailed data regarding maternal health and exposures during pregnancy. Logistic regression was used to examine the contribution of a wide range of pregnancy, birth and social factors to caesarean.Findings
28% of 4862 mothers were delivered by caesarean. The final adjusted analyses revealed that use of diabetes medication (OR = 3.1, 95% CI = 1.7–5.5, p < 0.001) and maternal mental health problems during pregnancy (OR = 1.3, CI = 1.1–1.6, p = 0.003) were associated with increased odds of caesarean. Young maternal age (OR = 0.6, CI = 0.5–0.7, p < 0.001), having two or more children (OR = 0.7, CI = 0.6–0.9, p < 0.001), and fathers having an unskilled occupation (OR = 0.7, CI = 0.6–1.0, p = 0.036) were associated with reduced odds of caesarean.Conclusion
Our findings raise the prospect that the effect of additional screening and support for maternal mental health on caesarean rate should be subject of prospective study. 相似文献107.
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In this article, we propose an extension of the Maxwell distribution, so-called the extended Maxwell distribution. This extension is evolved by using the Maxwell-X family of distributions and Weibull distribution. We study its fundamental properties such as hazard rate, moments, generating functions, skewness, kurtosis, stochastic ordering, conditional moments and moment generating function, hazard rate, mean and variance of the (reversed) residual life, reliability curves, entropy, etc. In estimation viewpoint, the maximum likelihood estimation of the unknown parameters of the distribution and asymptotic confidence intervals are discussed. We also obtain expected Fisher’s information matrix as well as discuss the existence and uniqueness of the maximum likelihood estimators. The EMa distribution and other competing distributions are fitted to two real datasets and it is shown that the distribution is a good competitor to the compared distributions. 相似文献
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To document the socioeconomic situation of street children in Iran and to ascertain the part played by this in becoming a street child, we classified and evaluated studies on this issue from the recent decade according to their strengths and weaknesses. The results will be helpful in policy‐making and planning for this group. The study employed a systematic review methodology, searching Iranian and international databases, and many universities and related organisations in Iran. After the quality of studies had been evaluated by three researchers, the findings of 40 research studies were classified, described and analysed. The research finds that street children in Iran come from crowded, low‐income families; many of them were rural–urban migrants and Afghans with families who immigrated to Iran; most of their parents had a lower than high school education and many of their fathers were unemployed or had low‐income jobs; the majority of these children were unskilled workers who would work many hours of the day for negligible incomes. We conclude that low socioeconomic status was prevalent among the street children's families in Iran and seems to be an important factor in the street‐connectedness of the children. 相似文献
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