ols

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)

利用R软件建立混合效应模型，对于不同随机效应参数的混合模型进行对比(develop the mixed-effects models and compare the goodness-of-fit)

说明：  spei的R语言计算版本 用于计算干旱指数spei(R language computing version of spei)

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

说明：  进行了常微分方程的建立，并模拟出经典的SIR模型曲线(The ordinary differential equation is established and the classical SIR model curve is simulated)

copula R语言，编程学习。享受copula学习的乐趣。R语言编程，copula代码(R copula)

说明：  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)

说明：  利用R语言，根据GARCH模型进行波动率的预测。(GARCH model is used to forecast volatility.)

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)

FAVAR。运用结构化变量进行因子分析，拟合VAR模型(FAVAR. Structural variables were used for factor analysis to fit the VAR model)