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In this article, we propose some tests of fit based on sample entropy for the composite Gumbel (Extreme Value) hypothesis. The proposed test statistics are constructed using different entropy estimates. Through a Monte Carlo simulation, critical values of the test statistics for various sample sizes are obtained. Since the tests based on the empirical distribution function (EDF) are commonly used in practice, the power values of the entropy-based tests with those of the EDF tests are compared against various alternatives and different sample sizes. Finally, two real data sets are modeled by the Gumbel distribution.KEYWORDS: Entropy estimator, Gumbel distribution, Monte Carlo simulation, test power 相似文献
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Sahar Ghale Askari Masomeh Khatbasreh Mohammad Hassan Ehrampoush Mohammad Hassan Sheikhha Hadi Eslami Mahmoud Taghavi Samira Shahrokhi Sodeh Andishmand 《Women and birth : journal of the Australian College of Midwives》2018,31(3):e204-e209
Problem
The process of industrialization and lifestyle changes have gradually exposed human ?societies to a larger number of environmental risk factors, which may cause hormonal ?abnormalities and congenital anomalies.Background
The current study aimed to investigate the relationship ?between environmental factors and hormonal abnormalities among pregnant women in Yazd, ?Iran.Methods
A hundred participants were randomly selected from among a group of pregnant women. According to the screening tests (AFP, free β-?HCG, uE3, PAPP-A, and inhibin-A) performed at the genome clinic in Yazd in 2016, the risk of Down Syndrome (DS) was sufficiently high in this group of pregnant women from which the participants were selected. A ?questionnaire was used to collect data on the degree of the participants’ exposure to pesticides ?at home, use of canned and fast foods, and consumption of greenhouse fruits. The collected data were ?analyzed by One-way ANOVA and Kruskal–Wallis Test.Findings
The mean of Multiple of Median (MoM) for inhibin-A was significantly higher among pregnant ?women who often or always used pesticides at home (p = 0.047). The mean MoM ?for free β-HCG was significantly higher among pregnant women who often or always used canned ?foods (p = 0.024). Finally, the mean MoM for uE3 (1.85 ± 1.30) was significantly higher among ?pregnant women who never consumed greenhouse fruits (p = 0.003).Conclusion
It can be concluded that it is possible to reduce environmental exposures affecting hormonal abnormalities among pregnant women by improving nutritional patterns, minimizing the use of pesticides at home, and reducing the intake of canned foods and greenhouse fruits. 相似文献44.
The use of logistic regression modeling has seen a great deal of attention in the literature in recent years. This includes all aspects of the logistic regression model including the identification of outliers. A variety of methods for the identification of outliers, such as the standardized Pearson residuals, are now available in the literature. These methods, however, are successful only if the data contain a single outlier. In the presence of multiple outliers in the data, which is often the case in practice, these methods fail to detect the outliers. This is due to the well-known problems of masking (false negative) and swamping (false positive) effects. In this article, we propose a new method for the identification of multiple outliers in logistic regression. We develop a generalized version of standardized Pearson residuals based on group deletion and then propose a technique for identifying multiple outliers. The performance of the proposed method is then investigated through several examples. 相似文献
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Ali S. Hadi 《Journal of applied statistics》1990,17(3):313-327
In the context of the general linear model Y=Xβ+ε, the matrix Pz =Z(ZTZ)?1 ZT , where Z=(X: Y), plays an important role in determining least squares results. In this article we propose two graphical displays for the off-diagonal as well as the diagonal elements of PZ . The two graphs are based on simple ideas and are useful in the detection of potentially influential subsets of observations in regression. Since PZ is invariant with respect to permutations of the columns of Z, an added advantage of these graphs is that they can be used to detect outliers in multivariate data where the rows of Z are usually regarded as a random sample from a multivariate population. We also suggest two calibration points, one for the diagonal elements of PZ and the other for the off-diagonal elements. The advantage of these calibration points is that they take into consideration the variability of the off-diagonal as well as the diagonal elements of PZ . They also do not suffer from masking. 相似文献
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Afkhami Ahmad Nasr Isfahani Ali Abzari Mahdi Teimouri Hadi 《Voluntas: International Journal of Voluntary and Nonprofit Organizations》2019,30(5):1036-1053
VOLUNTAS: International Journal of Voluntary and Nonprofit Organizations - Antecedents and consequences of employer-supported volunteering (ESV) have been widely studied. Yet, in the literature,... 相似文献
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Sobhan Shafiei Hadi Saboori Mahdi Doostparast 《Journal of Statistical Computation and Simulation》2017,87(2):267-279
This paper considers problems of interval estimation and hypotheses testing for the generalized Lorenz curve under the Pareto distribution. Our approach is based on the concepts of generalized test variables and generalized pivotal quantities. The merits of the proposed procedures are numerically carried out and compared with asymptotic and bootstrap methods. Empirical evidence shows that the coverage accuracy of the proposed confidence intervals and the type I error control of the proposed exact tests are satisfactory. For illustration purposes, a real data set on median income of the 20 occupations in the United States Census of Population is analysed. 相似文献
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Hadi Alizadeh Noughabi 《Journal of Statistical Computation and Simulation》2017,87(5):956-965
In this article, we consider the ranked set sampling (RSS) and investigate seven tests for normality under RSS. Each test is described and then power of each test is obtained by Monte Carlo simulations under various alternatives. Finally, the powers of the tests based on RSS are compared with the powers of the tests based on the simple random sampling and the results are discussed. 相似文献
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Hadi Alizadeh Noughabi 《统计学通讯:模拟与计算》2017,46(7):5531-5540
The logistic distribution is one of the fundamental distribution and is widely used for describing model growth curves in survival analysis and biological studies. Applications of this distribution are presented in statistical literature. In this article, goodness of fit tests for the logistic distribution based on the empirical distribution function (EDF) are considered. In order to compute the test statistics, because the MLEs cannot be obtained explicitly, we use the approximate maximum likelihood estimates (AMLEs) suggested by Balakrishnan and Cohen (1990), which are simple explicit estimators. Power comparisons of the considered tests are carried out via simulations. Finally, two illustrative examples are presented and analyzed. 相似文献