stata出现unknown egen function mean() 原代码这么写的
// 生成同行业 均值
bysort year Indcd:egen ROE_mean=mean(ROE)
bysort year Indcd:egen ROA_mean=mean(ROA)
bysort year Indcd:egen ROS_mean=mean(ROS)
bysort year Indcd:egen EM_mean=mean(EM)
bysort year Indcd:egen TurnOver_mean=mean(TurnOver)