期刊文献+
共找到2篇文章
< 1 >
每页显示 20 50 100
工程制图中形体尺寸标注完整性的分析 被引量:2
1
作者 薛爱文 杨胜强 《机械管理开发》 2004年第5期7-8,10,共3页
分析形体表面投影特性与图形元素之间的关系,提出了一种“空间元素投影特征识别法”,并从线面分析法角度论证了此法的可行性。
关键词 一般形体 投影特性 尺寸完整性 空间元素投影特征识别法
下载PDF
General Classes of Variance Estimators in Simple Random Sampling Using Multi-auxiliary Variables
2
作者 Zahoor Ahmad Shoaib Ali Muhammad Hanif 《Journal of Mathematics and System Science》 2013年第5期262-269,共8页
Srivastava and Jhajj [ 1 6] proposed a class of estimators for estimating population variance using multi auxiliary variables in simple random sampling and they utilized the means and variances of auxiliary variables.... Srivastava and Jhajj [ 1 6] proposed a class of estimators for estimating population variance using multi auxiliary variables in simple random sampling and they utilized the means and variances of auxiliary variables. In this paper, we adapted this class and motivated by Searle [13], and we suggested more generalized class of estimators for estimating the population variance in simple random sampling. The expressions for the mean square error of proposed class have been derived in general form. Besides obtaining the minimized MSE of the proposed and adapted class, it is shown that the adapted classis the special case of the proposed class. Moreover, these theoretical findings are supported by an empirical study of original data. 展开更多
关键词 Variances estimation multi-auxiliary variables simple random sampling mean square errors.
下载PDF
上一页 1 下一页 到第
使用帮助 返回顶部