v21i04.R

说明：  葡萄酒数据集， 基于Wine数据集的数据分析报告 R语言+实验结果文档(Wine datasets Data Analysis Report R Language + Experimental Results Document Based on Wine Data Set)

R语言对数据进行Garch-t-Copula建模和Garch-Clayton-Copula建模(Garch-t-Copula modeling and Garch-Clayton-Copula modeling for data in R language)

双重差分估计 双重差分模型（difference-in-difference，DID）近年来多用于计量经济学中对于公共政策或项目实施效果 的定量评估。 通常大范围的公共政策有别于普通科研性研究，难以保证对于政策实施组和对照组在样本分配上的完全随机。非随机分配政策实施组和对照组的试验称为自然试验（naturaltrial），此类试验存在较显著的特点，即不同组间样本在政策实施前可能存在事前差异，仅通过单一前后对比或横向对比的分析方法会忽略这种差异，继而导致对政策实施效果的有偏估计。(Quantitative evaluation of policy or project implementation effect. Generally, a wide range of public policies is different from general scientific research, and it is difficult to ensure that the sample allocation for the policy implementation group and the control group is completely random. The non-randomly assigned policy implementation group and the control group are called natural trials, which have significant characteristics, i.e. there may be prior differences between the different groups of samples before the implementation of the policy, and this difference will be ignored only through a single pre-and post-comparison or horizontal comparison analysis method, which leads to the policy. Biased estimation of implementation)

成都市空气中的O3来源及分析，可用于大创项目(O3 source and analysis in air of Chengdu, which can be used in some projects)

these of diagnosis electrical machine

SIR。。。。 传染病传播的SIR模型，很全，可直接应用仿真模拟 (SIR model the spread of infectious diseases, it is full, the simulation can be applied directly)(SIR model the spread of infectious diseases, it is full, the simulation can be applied directly)

说明：  基于R语言的空气质量数据分析与预测，包括可视化方法处理数据、回归分析与预测(R code for air quality data analysis and prediction)

说明：  The source code of data analysis using R language does not contain data sets. If you need to contact us

在R中如何导入数据，主要是txt，csv，excel等数据格式的导入(how to imput data in R)

说明：  数据集实体文件名称：中国降水日值0.5°×0.5°格点数据集文件命名由数据集代码（SURF_CLI_CHN_PRE_DAY_GRID_0.5）、年月日标识（YYYYMMDD）组成。具体形式：SURF_CLI_CHN_PRE_DAY_GRID_0.5-YYYYMMDD.TXT(Specific form:SURF_CLI_CHN_PRE_DAY_GRID_0.5-YYYYMMDD.TXT)