连老师:
下面的命令问题在哪里?
. xi:xtivreg2 efficency_2w i.power1 board3 committee_2 shrcr1 shrs growth gross_profit (market=gdp1 ) jobless c.board3#c.market c.committee_2#c.market,fe robust
我是想用xtivreg2进行异方差稳健型估计,输入上面的命令之后,一直提示错误:
cboard3#c: operator invalid
我把交乘项删去后,是提示信息如下:
Warning - singleton groups detected. 123 observation(s) not used.
Error: must have ranktest version 01.2.02 or greater installed
Currently installed version is 01.1.03
To update, from within Stata type .
请问连老师:如何对命令版本进行升级呢?
我希望保留交乘项,并利用xtivreg2进行异方差稳健型估计,对于上面的命令应该怎么修改呢?