命令:xtfrontier y labour capital year capital#capital labour#labour year#year capital#labour capital#year labour#year,tvd
为什么运行stata时会出现错误?命令格式不对吗?谢谢
注:y labour capital 均为对数形式 . xtfrontier y labour capital year capital#capital labour#labour year#year capital#labour capital#year labour#year,tvd capital: factor variables may not contain noninteger values
some independent variables collinear with the dependent variable
r(452); end of do-file