查询词典 sample interval

Describes general methods of point and interval parameter estimation and the small and large sample properties of estimators: method of moments, maximum likelihood, unbiased estimation, Rao-Blackwell and Lehmann-Scheffe theorems, information inequality, asymptotic relative efficiency of estimators.

点估计和区间估计的一般方法，估计量的小样本和大样本性质：矩法，极大似然估计，无偏估计，Rao-Blackwell 和 Lehmann-Scheffe 理论，信息不等式，渐进相对有效估计量。

We then calculate the sample average and the standard deviation to construct confidence interval, and the related t statistic.

计算样本均值，标准差和对应的置信区间以及t值。

For fitting ROC curves and getting the area under the ROC curve, we applied the parametric methods of binormal models and ordinal regression models, the semiparametric method of Cox proportional hazards model, the nonparametric methods of Hanley, Delong This paper also include estimation of required sample size, evaluation of confounding effects, and estimation of standard error and confidence interval by resampling method for ROC analysis.

目前该模型用于ROC分析的统计学方法比较完善，属于"经典"的ROC分析参数法。本文探讨了单变量、双变量双正态ROC模型的构建及其参数的最大似然估计方法；采用双变量卡方检验、真阳性率z检验、面积z检验三种方法比较了ROC曲线间是否具有显著性差异。

Events,Operation and Relation of Sets, Classical Probability, Geometrical Probability , Statistical Stability of a Frequency, Axioms of Probability, Conditional Probability, Total Probability Theorem, Bayes' Rule,Independent Events,Independent Repeated Trials, One Dimensional Random Variables, Discrete Random Variables, Distribution Function of a Random Variables , Continuous Random Variables, Normal Distribution, Distribution of a Function of a Random Variable, Multidimensional Random Variables, Joint Distribution Function, Marginal Distribution Function,Discrete Two—Dimensional Random Variables,Continuous Two—Dimensional Random Variables, Independent Random Variables, Distribution of Functions of Random Variables,Expectation,Variance, Covariance, Coefficient of Correlation, Bivariate Normal Distribution, Law of Large Numbers, The Central Limit Theorems, Sample and Population ,Chi—Squared, T and F Distributions , Sampling Distributions , Point Estimation , Interval Estimation , Testing Hypotheses , A Test of Significance for Parameters in a Single Sample From a Normally Distributed Population , A Test of Significance for Parameters in Two Sample From Normally Distributed Populations .

本课程的主要内容：概率的概念与运算、随机变量及其分布、随机变量的数字特征与极限定理、数理统计的基本概念、估计和检验的基本方法，随机事件与概率随机事件、事件的关系与运算、几何概率、统计概率等，条件概率、全概率公式、贝叶斯公式、事件的独立性、二项概率公式，随机变量的概念、离散型随机变量、随机变量的分布函数、连续型随机变量、随机变量函数的分布，多维随机变量及其分布函数、边缘分布函数、随机变量的独立性、二维随机变量函数的分布，数学期望、方差、协方差和相关系数、大数定律、中心极限定理，总体与样本， X 2-分布、 t-分布和 F-分布，统计量及抽样分布，假设检验的基本概念、单个正态总体参数的显著性检验、两个正态总体参数的显著性检验。

Data Analysis: Assuming a 0% event rate in patients with D-dimer levels between 200 and 500 ng/mL, a sample of 450 patients would result in a 95% confidence interval upper limit of 0.6%.

数据分析：假设D-二聚体水平在200~500ng/ml之间的患者概率事件为0%，则450例患者的样本产生的95%可信区间上限为0.6%。

These spacings are valueswithin the interval[0,1]such that the inverse of cumulative distribution function atlarge sample quantiles is equal to the value of spacings.

这些线性估计依赖于被选择的顺序统计量，而顺序统计量的秩由一些间隔所确定，这些间隔是大样本分位数依分布函数的反函数在区间[0，1]上确定的数值。

A kind of probability sample in which a set interval is applied to a list often population to identity elements included in the sample (e.g., picking every 10th name).

以一定的间隔来从人口名单中抽取所需的样本(如：每隔10个人抽取一次)。

Assume β=1, and confidence level is 0.95, the length of normal confidence interval is compared to the length of shortest confidence interval, the results show: both absolute difference d and relative difference e are decreased by the increasing sample number n, when n≤9, e≥10%.

在假设参数β=1，置信水平为0.95的条件下，比较了常用置信区间与最短置信区间的长度，结果表明：两者长度的绝对差d和相对差e均随样本容量n的增大而减小，当n≤9时，e≥10%。

Based on this idea, the author has chosen two typical loess sections of Luochuan, and Xifeng for this study, collected the successive loess columns; To probe the conditional experiments of BeO sample preparation and measurement, and improve the existing method; On the basis of the technology improvement, the author has finished 402 samples' BeO preparation and AMS measurement; Also at the same time, to separate quartz from samples at 1 cm interval for both Luochuan and Xifeng sections systematically, to carry out measurements of quartz grain-size, SUS, grey scale, carbonate content and bulk sample density; By using the grain size model, the author has set up the chronological framework for both Luochuan, and Xifeng sections and the time sequence of millennial scale abrupt climate events recorded in loess strata, and reconstructed the East Asian monsoon history over 130ka by using multi proxies; Finally, to discuss the possible mechanisms of palaeoclimatic changes tentatively.

详细地球科学的发展离不开高精度和高分辨率的研究。运用长寿命核素如〓Be作为环境过程的示踪，已成为不可替代的有效工具。本论文选择洛川、西峰两个典型的黄土剖面，连续采集柱状样；探索了BeO样品制备、测量的条件实验，改进了原有的方法，完成了402个BeO样品的制备和AMS测量；同时还系统地分离洛川、西峰剖面高分辨率（1cm）黄土、古土壤样品中的碎屑石英，测量了碎屑石英粒度，以及全样的磁化率、灰度、碳酸盐含量和容重等古气候代用指标；采用粒度年代模式建立了洛川剖面和西峰剖面的年代标尺，建立了黄土地层记录的千年尺度的气候突变事件的时间序列，多指标重建了最近130ka东亚季风变迁史；初步讨论了古气候变迁的可能机制。

Numerical simulations by assemblies of circular panicles can qualitatively reflect the general characteristics of liquefaction behavior of sand. The interval effect of aspect ratio of elliptical panicle on the mechanical behavior of numerical sample is obtained, and the reason is related to the initial average co-ordination number. The regularity of evolution of fabric in the process of sand liquefaction under cyclic loading can be qualitatively achieved by using the numerical sample randomly mixed of panicles with different shapes. Numerical simulations can not only demonstrate the macro phenomenon of particle breakage, mostly importantly, it can also expose the evolution of particle breakage microscopically, and would contribute to further research of the micromechanics of particle breakage.

研究结果表明：Hertz-Mindlin非线性接触模型适用于变围压条件下砂土力学性质模拟；纯圆颗粒模拟能够定性地反映饱和砂土振动液化的一般规律；颗粒长短比变化对砂土力学性质的影响具有区间效应，其原因与粒间初始平均接触数有关；不同形状随机混合试样能够从定性规律上反映振动液化过程中砂土的细观组构演化规律；数值模拟不仅可得到颗粒破碎宏观响应，而且可以分析内部接触力变化和实现对粘结破裂位置的追踪，从而可进一步研究颗粒破碎细观力学机制。

This one mode pays close attention to network credence foundation of the businessman very much.

这一模式非常关注商人的网络信用基础。

Cell morphology of bacterial ghost of Pasteurella multocida was observed by scanning electron microscopy and inactivation ratio was estimated by CFU analysi.

扫描电镜观察多杀性巴氏杆菌细菌幽灵和菌落形成单位评价遗传灭活率。