科学软件网是一个以引进国外科研软件,提供*软件服务的营业网站,网站由北京天演融智软件有限公司创办,旨在为国内高校、科研院所和以研发为主的企业事业单位提供的科研软件及相关软件服务。截止目前,科学软件网已获得数百家****软件公司正式授权,代理销售科研软件达一千余种,软件涵盖领域包括经管,仿真,地球地理,生物化学,工程科学,排版及网络管理等。同时,还提供专业培训、课程(包含34款软件,66门课程)、实验室解决方案和项目咨询等服务。Stata是一款完整的、集成的统计软件包,提供您需要的一切数据分析、数据管理和图形。统计功能介绍Stata使得大量的统计工具用于指尖标准方法,如基本表格和总结案例对照分析ARIMAANOVA 和MANOVA线性回归时间序列平滑广义线性模型(GLM)聚类分析对比和比较功率分析样本选择……**方法,如多层模型生存分析动态面板数据回归结构方程建模二进制,计数和审查结果ARCH多重替代法调查数据Treatment effects精确统计贝叶斯分析……Stata是一个统计分析软件,但它也具有很强的程序语言功能,这给用户提供了一个广阔的开发应用的天地,用户可以充分发挥自己的聪明才智,熟练应用各种技巧,真正做到随心所欲。事实上,Stata的ado文件(**统计部分)都是用Stata自己的语言编写的。Stata其统计分析能力远远**过了SPSS,在许多方面也**过了SAS!由于Stata在分析时是将数据全部读入内存,在计算全部完成后才和磁盘交换数据,因此计算速度较快(一般来说, SAS的运算速度要比SPSS至少快一个数量级,而Stata的某些模块和执行同样功能的SAS模块比,其速度又比SAS快将近一个数量级!)Stata也是采用命令行方式来操作,但使用上远比SAS简单。其生存数据分析、纵向数据(重复测量数据)分析等模块的功能甚至**过了SAS。用Stata绘制的统计图形相当精美,很有特色。科学软件网是一个以引进国外优秀科研软件,提供*软件服务的营业,由天演融智软件有限公司创办,旨在为国内高校、科研院所和以研发为主的企业事业单位提供优秀的科研软件及相关软件服务。截止目前,科学软件网已获得数百家****软件公司正式授权,代理销售科研软件达一千余种,软件涵盖领域包括经管,仿真,地球地理,生物化学,工程科学,排版及网络管理等。同时,还提供专业培训、视频课程(包含34款软件,64门课程)、实验室解决方案和项目咨询等服务。不管您是需要购买单款软件,还是制定整个实验室的购买方案,都可以提供。Lasso is a machine-learning technique used for model selection, prediction, and inference.The new lasso command selects “optimal” predictors for continuous, count, and binary outcomes using deviances from linear, Poisson, logit, or probit regression models.For instance, if you type. lasso linear y x1-x500lasso will select a subset of the specified covariates—say, x2, x10, x11, and x21. You can then use the standard predict command to obtain predictions of y.If you instead have a binary or count outcome, you can use lasso logit, lasso probit, or lasso poisson in the same way. And if you prefer to select variables using the elastic net or square-root lasso method, you can use the elasticnet or sqrtlasso command.Sometimes, variable selection or prediction is the final goal of lasso. Other times, you are interested in estimating and testing coefficients. Stata 16 provides 11 commands that allow you to estimate coefficients, standard errors, and confidence intervals and to perform tests for variables of interest while using lasso methods to select from among potential control variables. The commands aredsregress, dslogit, dspoisson, poregress, pologit, popoisson, poivpoisson, xporegress, xpologit,xpopoisson, and xpoivregress.The ds commands perform double-selection lasso, the po commands perform partialing-out lasso, and the xpo commands perform cross-fit partialing-out lasso. They do this for models with continuous, binary, and count outcomes. They can even handle endogenous covariates in models for continuous outcomes. The literature currently discusses many methods for lasso-based inference. We make some of these methods available so that researchers can select their favorite. In fact, there are even more lasso-based methods of inference in the literature, and often researchers may use the tools available in lasso, sqrtlasso, and elasticnet to implement other methods.The lasso and elasticnet commands are standard lasso tools often requested for variable selection and prediction. The lasso tools for inference implement newer methods developed primarily by econometricians. However, these inference methods will be popular in all disciplines because they provide a method for testing and interpreting coefficients on variables of interest.Users can easily learn all about the lasso features in the new Lasso Reference Manual.统计功能介绍Stata使得大量的统计工具用于指尖● 基本表格和总结● 案例对照分析● ARIMA● ANOVA 和MANOVA● 线性回归● 时间序列平滑● 多层模型● 生存分析● 动态面板数据回归● 结构方程建模● 二进制,计数和审查结果● ARCH■ 标准方法,如■ **方法,如● 多重替代法● 调查数据● Treatment effects● 精确统计● 贝叶斯分析● ……Stata 16 New in Bayesian analysis—Multiple chains, predictions, and moreMultiple chains.Bayesian inference based on an MCMC (Markov chain Monte Carlo) sample is valid only if the Markov chain has converged. One way we can evaluate this convergence is to simulate and compare multiple chains.The new nchains() option can be used with both the bayes: prefix and the bayesmh command. For instance, you type. bayes, nchains(4): regress y x1 x2and four chains will be produced. The chains will be combined to produce a more accurate final result. Before interpreting the result, however, you can compare the chains graphically to evaluate convergence. You can also evaluate convergence using the Gelman–Rubin convergence diagnostic that is now reported by bayes: regress and other Bayesian estimation commands when multiple chains are simulated. When you are concerned about noncovergence, you can investigate further using the bayesstats grubin command to obtain individual Gelman–Rubin diagnostics for each parameter in your model.Bayesian predictions.Bayesian predictions are simulated values from the posterior predictive distribution. These predictions are useful for checking model fit and for predicting out-of-sample observations. After you fit a model with bayesmh, you can use bayespredict to compute these simulated values or functions of them and save those in a new Stata dataset. For instance, you can type. bayespredict (ymin:@min({_ysim})) (ymax:@max({_ysim})), saving(yminmax)to compute minimums and maximums of the simulated values. You can then use other postestimation commands such as bayesgraph to obtain summaries of the predictions.The dataset created by bayespredict may include thousands of simulated values for each observation in your dataset. Sometimes, you do not need all of these individual values. To instead obtain posterior summaries such as posterior means or medians, you can use bayespredict, pmean or bayespredict, pmedian. Alternatively, you may be interested in a random sample of the simulated values. You can use, for instance, bayesreps, nreps(100) to obtain 100 replicates.Finally, you may want to evaluate model goodness of fit using posterior predictive p-values, also known as PPPs or as Bayesian predictive p-values. PPPs measure agreement between observed and replicated data and can be computed using the new bayesstats ppvalues command. For instance, using our earlier example. bayesstats ppvalues {ymin} {ymax} using yminmax科学软件网的客户涵盖产品涵盖教育、、交通、通信、金融、保险、电力等行业,并且为诸如北京大学、清华大学、中国大学、中科院、农科院、社科院、环科院、国家、交通部、南方电网、国家电网、许继、南瑞等国内大型企事业单位、部委和科研机构长期提供相关产品。我们的品质,值得您信赖。