Bayesian inference for the mean and standard deviation of a normal population when only the sample size,mean and range are observed

Consider a random sample X₁, X₂,…, X_n, from a normal population with unknown mean and standard deviation. Only the sample size, mean and range are recorded and it is necessary to estimate the unknown population mean and standard deviation. In this paper the estimation of the mean and standard deviation is made from a Bayesian perspective by using a Markov Chain Monte Carlo (MCMC) algorithm to simulate samples from the intractable joint posterior distribution of the mean and standard deviation. The proposed methodology is applied to simulated and real data. The real data refers to the sugar content (^oBRIX level) of orange juice produced in different countries.     

存货投资模型及其预测

利用多元线性回归模型对日常经济生活有重大影响的存货投资进行了经济建模，并对此进行了经济意义检验、统计检验、计量经济学检验和模型预测检验，最终确立了所需要的计量经济学模型，可在一定范围内对存货投资未来的变化进行预测，并可根据预测得到的结论出发，在现阶段采取各种相应的政策和措施，使各种资源配置达到最优．     

预科数学教学中渗透建模思想的几点尝试

数学建模就是应用数学知识解决实际问题,根据数学教学中研究新理论和数学教学实践新需要,对预科数学教学中渗透建模思想提出了几点尝试。     

用数理统计方法评估试卷质量

用数理统计的方法,通过对某一次考试成绩的分析研究,确定出这次考试的可信度、难度、覆盖度、区分度,对考试进行了科学合理的统计分析.     

基于细胞逻辑、形态特征图像分割新算法

在MATLAB软件中结合细胞逻辑形态特征提出了一种图像分割和计数的新算法这种算法的主要思想是通过逻辑运算拉氏变换和数学形态学运算的处理首先提取细胞图像中的逻辑信息再根据细胞特有的圆形椭圆形形态特征将细胞从整个背景中进行分割处理并根据逻辑信息形态特征实现了血细胞图像的简单计数实现了特定血细胞的单独分割其算法简单可靠     

从《学报》引文研究高校教研人员的文献利用

采用引文分析法 ,以《学报》引文为例 ,就引文量、文献类型、语种分布、引文年代分布、自引状况及论文的合作度等进行了分析研究 ,反映了长安大学文献利用实况 ,提出了如何满足读者对科技文献需求的建议和方法     

论德育数学模型的运用

本文从数学模型的内涵与作用入手 ,探讨了数学模型在思想道德素质教育、大学生恋爱教育、成才教育的运用     

Cryptosporidium Dose Response Studies: Variation Between Isolates

The infectivity of three different isolates of the waterborne protozoan parasite Cryptosporidium parvum has been tested in human feeding studies. These three isolates (Iowa, TAMU, and UCP) have different ID50s, indicating substantial variation in their infectivity for humans. This finding is of great importance for quantitative risk assessment as it provides strong evidence for heterogeneity in infectivity among isolates of the same species.     

The Beta Poisson Dose-Response Model Is Not a Single-Hit Model

The choice of a dose-response model is decisive for the outcome of quantitative risk assessment. Single-hit models have played a prominent role in dose-response assessment for pathogenic microorganisms, since their introduction. Hit theory models are based on a few simple concepts that are attractive for their clarity and plausibility. These models, in particular the Beta Poisson model, are used for extrapolation of experimental dose-response data to low doses, as are often present in drinking water or food products. Unfortunately, the Beta Poisson model, as it is used throughout the microbial risk literature, is an approximation whose validity is not widely known. The exact functional relation is numerically complex, especially for use in optimization or uncertainty analysis. Here it is shown that although the discrepancy between the Beta Poisson formula and the exact function is not very large for many data sets, the differences are greatest at low doses--the region of interest for many risk applications. Errors may become very large, however, in the results of uncertainty analysis, or when the data contain little low-dose information. One striking property of the exact single-hit model is that it has a maximum risk curve, limiting the upper confidence level of the dose-response relation. This is due to the fact that the risk cannot exceed the probability of exposure, a property that is not retained in the Beta Poisson approximation. This maximum possible response curve is important for uncertainty analysis, and for risk assessment of pathogens with unknown properties.     

影响数学学术期刊发表时滞的因素及其对策分析

分析了影响数学学术期刊发表时滞的主要因素是:编辑工作不到位,审稿人选择失当,排版印刷出现漏洞,作者不配合工作等,并从编辑、审稿、印刷出版和作者几方面提出相应的对策。