CHP01 - Introduction

1. Stata 特点

短小精悍，界面灵活
运算速度极快
绘图功能卓越
帮助详尽
过程可重复性
更新和发展速度快

2. Stata 版本

which stata is right for me
Stata/MP: The fastest version of Stata (for quad-core, dual-core, and multicore/multiprocessor computers) that can analyze the most data
Stata/SE: Stata for large datasets
Stata/IC: Stata for mid-sized datasets
Numerics by Stata: Stata for embedded and web applications

Stata/MP is the fastest and largest version of Stata. Virtually any current computer can take advantage of the advanced multiprocessing of Stata/MP. This includes the Intel i3, i5, i7, i9, Xeon, Celeron, and AMD multi-core chips. On dual-core chips, Stata/MP runs 40% faster overall and 72% faster where it matters, on the time-consuming estimation commands. With more than two cores or processors, Stata/MP is even faster. Find out more about Stata/MP.

Stata/MP, Stata/SE, and Stata/IC all run on any machine, but Stata/MP runs faster. You can purchase a Stata/MP license for up to the number of cores on your machine (maximum is 64). For example, if your machine has eight cores, you can purchase a Stata/MP license for eight cores, four cores, or two cores.

Stata/MP can also analyze more data than any other flavor of Stata. Stata/MP can analyze 10 to 20 billion observations given the current largest computers, and is ready to analyze up to 1 trillion observations once computer hardware catches up.

Stata/SE and Stata/IC differ only in the dataset size that each can analyze. Stata/SE (up to 10,998) and Stata/MP (up to 65,532) can fit models with more independent variables than Stata/IC (up to 798). Stata/SE can analyze up to 2 billion observations.

Stata/IC allows datasets with as many as 2,048 variables and 2 billion observations. Stata/IC can have at most 798 independent variables in a model.

Numerics by Stata can support any of the data sizes listed above in an embedded environment.

All the above flavors have the same complete set of features and include PDF documentation.

3. Stata 功能

数据管理
制表绘图
统计模型
复杂建模
编程

4. Stata 概貌

五个窗口，一个菜单条
三种执行命令的方式
- 菜单
- 交互命令
- do file

5. do file 使用

打开do文档编辑器 doedit
保存和关闭

优化do文档

尽量加入注释语句：*；/**/；//

sum price weight  /*变量的基本统计量*/ 
// 产生一个新的变量
gen x = 5

断行的三种方式： “///” 、 “/* */” 、 #delimit 命令

twoway (scatter price weight) ///
       (lfit price weight),    /*
       */title("散点图和线性拟合图")

#delimit ;
twoway (scatter price wei)
       (lfit price wei),
       title("散点图和线性拟合图");
#delimit cr

执行 do 文档
doedit chp01.do
do chp01.do

6. 使用 log 文件

log using 文件名.log, 选项
cmdlg using 文件名.log, 选项
*log using d:\stata10\ado\personal\stata.log, text replace
*cmdlog using d:\stata10\ado\personal\command.log, append

7. Stata命令结构

[prefix: ] command [varlist] [=exp] [if exp] [in range] [weight] [, options]

[prefix: ] command [varlist] [=exp] [if exp] [in range] [weight] [, options]
- 命令名可以用缩写，Stata的帮助文件中用下划线标注了命令的缩写标准
- 例：list–l 、display–dis、summarize–sum、generate–gen、regress–reg

[prefix: ] command [varlist] [=exp] [if exp] [in range] [weight] [, options]
- varlist 表示一个变量，或者多个变量，如有多个变量，需用空格隔开。
- 可以一一列出变量名，也可使用一些简便方法（“-”、通配符、正则表达式）
- 通常因变量在前，自变量在后

[prefix: ] command [varlist] [=exp] [if exp] [in range] [weight] [, options]
- 前缀与命令前用“:”隔开
- 最常见的前缀是by varlist，使用该前缀表示对varlist的每个取值分别执行一遍命令
  - by foreign : sum price 使用by varlist前首先按照varlist对数据排序
  - by foreign, sort: sum price 使用by varlist, sort则可不必管数据是否已排序

[prefix: ] command [varlist] [=exp] [if exp] [in range] [weight] [, options]
- 该选项主要用于给新变量赋值或替换原变量的值
- gen newprice=price/1000
- list price newprice

[prefix: ] command [varlist] [=exp] [if exp] [in range] [weight] [, options]
- 对满足条件的个案执行命令
- list make price if foreign==0
- $==$ 、 $!=$ 、 $<=$ 、 $>=$ 、 $<$ 、 $>$ 、 $\&$ 、 $|$ 、 $\sim$

[prefix: ] command [varlist] [=exp] [if exp] [in range] [weight] [, options]
- 对编号在一定范围内的个案执行命令
  - list price in 5
  - list price in 1/5
  - list price in -5

[prefix: ] command [varlist] [=exp] [if exp] [in range] [weight] [, options]
- Stata有四种权重
  - fw，频率权数，重复观测的频数，必须为整数
  - pw，抽样权数，个案被抽中概率的倒数
  - aw，观测值方差的倒数，仅用于一些特殊的场合
  - iw，与观测值的“重要性”呈正比，不同命令对重要性的定义有所不同。

[prefix: ] command [varlist] [=exp] [if exp] [in range] [weight] [, options]
- 位于命令最后，与之前部分用“,”隔开（英文输入状态）
- 选项是命令功能的细化，Stata命令的选项非常丰富，这使得 Stata的功能异常强大
- 选项也可以使用缩写
  - sum price, d
  - tab foreign, sum(price)

Stata学习资源

help
MANUAL docs

Stata官网	Stata论坛	Stata课程	Stata其他资源
Stata.com Stata-FAQ Stata-Blogs Stata-资源链接	Stata-list Stack-Overflow 经管之家-人大论坛	UCLA在线课程 Princeton在线课程	Stata书单 Stata连享会-知乎 Stata资源汇总