排序方式: 共有11条查询结果,搜索用时 15 毫秒
1.
Dinesh S. Bhoj Mohammad Ahsanullah 《Biometrical journal. Biometrische Zeitschrift》1993,35(3):355-359
The test statistics are proposed for testing the equality of the coefficients of variation of two normal populations based on independent samples. The asymptotic distributions of the statistics are approximated by well-known distributions. The empirical sizes and powers of these statistics are computed and compared. 相似文献
2.
Valery B. Nevzorov Mohammad Ahsanullah 《Biometrical journal. Biometrische Zeitschrift》2000,42(8):1069-1081
In this paper we discuss the properties of concomitants of record values. The distributions of the concomitants in the sequence of record values of bivariate distributions are obtained and their possible applications in the areas of biosciences have been pointed out. 相似文献
3.
Dinesh S. Bhoj Mohammad Ahsanullah 《Biometrical journal. Biometrische Zeitschrift》1993,35(7):791-799
Consider the two linear regression models of Yij on Xij, namely Yij = βio + βil Xij + εij,j = 1,2,…,ni, i = 1,2, where εij are assumed to be normally distributed with zero mean and common unknown variance σ2. The estimated value of a mean of Y1 for a given value of X1 is made to depend on a preliminary test of significance of the hypothesis β11 = β21. The bias and the mean square error of the estimator for the conditional mean of Y1 are given. The relative efficiency of the estimator to the usual estimator is computed and is used to determine a proper choice of the significance level of the preliminary test. 相似文献
4.
M. Ahsanullah 《Biometrical journal. Biometrische Zeitschrift》1981,23(7):715-717
A sequence {Xn, n≤1} of independent and identically distributed random values with continuous cumulative distribution function F(x) is considered. Xj is a record value of this sequence if Xj ≤ max (X1, X2, …, Xj?1). We define L(n)=min.(j!j>L(n?1.), Xj<XL(n?1)), with L(0) = 1. Let Zn=XL(n)? XL(n?1), n ≤ 1. We will show that the conditional variance of Zn given XL(n?1)=x does not depend on × if and only if F(x) is exponential. 相似文献
5.
S.E. Ahmed D.S. Bhoj M. Ahsanullah 《Biometrical journal. Biometrische Zeitschrift》1998,40(6):737-751
Pooling data, when justified, is advantageous for estimating the true parameter. In this paper the problem of estimating the coefficient of variation is considered when it is a priori suspected that two coefficients of variation are the same. Various estimators based on pretest and shrinkage rules are considered. A comparison through the Simulated Mean Squared Error (SMSE) criterion is carried out among various proposed estimators of the target coefficient of variation. The relative simulated efficiencies of the restricted, shrinkage restricted and shrinkage pretest estimators are studied. It is found that the proposed estimators are quite robust when the sample sizes are not too large. The result of Monte Carlo study indicates that the proposed shrinkage pretest estimator is efficient than the usual estimator in a wider range. 相似文献
6.
M. Ahsanullah 《Biometrical journal. Biometrische Zeitschrift》1991,33(7):861-864
Infinite divisibility condition and a relation between the mean and variance are used to characterize the generalized negative binomial distribution. 相似文献
7.
M. Ahsanullah 《Biometrical journal. Biometrische Zeitschrift》1987,29(7):885-888
Suppose X1, X2,…, Xn are independent and identically distributed random variables with absolutely continuous distribution function F. It is known that if F is standard normal distribution then (i)∑X2i is a chi-square with n degrees of freedom and (ii)nX¯2 is a chi-square with 1 degrees of freedom where X¯=1/n ∑Xi. Here the above two properties are utilized to characterize the normal distribution. 相似文献
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9.
Ali Haider Unar Ahsanullah Dil Sobia Ali Imtiaz Khan Khalid Khan Ihsan Shi Qinghua 《Molecular biology reports》2022,49(7):6261-6268
Molecular Biology Reports - Fascins belong to a family of actin-bundling proteins that are involved in a wide range of biological functions. FSCN3, a newly identified testis-specific actin-bundling... 相似文献
10.
Dinesh S. Bhoj Mohammad Ahsanullah 《Biometrical journal. Biometrische Zeitschrift》1994,36(2):153-163
Consider the two linear regression models of Yij on Xij, namely Yij = βio + βij, Xij + Eij = 1, 2,…, ni, i = 1, 2, where Eij are assumed to be normally distributed with zero mean and common unknown variance σ2. The problem of estimating the conditional mean of Y1 for a given value of X1 is considered when it is a priori suspected that β10 = β20 and β11 = β21. The preliminary test estimator is proposed. The exact expressions for the bias and the mean square error of the estimator are derived. The relative efficiency of the new estimator to the usual least square estimator based on the first regression alone is computed and is used to determine the appropriate value of the significance level of the preliminary test β10 = β20 and β11 = β21. 相似文献