v21i04.R

从GEO数据库下载原始数据，提取数据中的表达值(Download raw data from the GEO database and extract the expression values in the data)

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)

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)

一篇论文的GARCH in mean VAR(GARCH in mean VAR of a published paper)

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

《时间序列分析及应用：R语言，潘红宇》书籍分享(Time Series Analysis and Application: R Language, Pan Hongyu)

实现xgboost算法，对实现分类和预测具有良好的效果(The implementation of xgboost algorithm has a good effect on classification and prediction)

关于时间序列的蒙特卡洛模拟,涉及一些简单的时间序列模型(monte carlo simulation of time series)

制作pcoa、饼图、venn图、热图、柱状图的脚本，可直接改参数使用，内有注释，适用于微生物多样性(the Script to make PCOA)

说明：  通过本书，读者不仅能掌握使用R及相关算法包来快速解决实际问题的方法，而且能从实际问题分析入手，到利用R进行求解，以及对挖掘结果进行分析的全面训练(Through this book, readers can not only master the method of using R and relevant algorithm packages to quickly solve practical problems, but also start from the analysis of practical problems to the comprehensive training of using R to solve problems and analyzing mining results)