定义
- X标准化：
- X中心化：
命令 center
安装
center为外部命令，需要事先安装。
ssc install center
语法
center varlist [,inplace { prefix(prefix) | generate(newvar) } standardize ]
解释：
centers (or, optionally, standardizes) the variables in varlist. For each varname in varlist, a new variable c_varname is created containing the centered (or standardized) values of that variable.
