reg 流动儿童比例 la01 la06 lb01 lc08 lc1001 lc1002 lstmedu lstfedu lsteco_3c lhrc04 lchna02 lchna04 lchna07 lmatb02 lmatb04 lmatb07 lengb02 lengb04 lengb07 lengb07std  lmatb02std ,r
reg 流动儿童比例 la01 la06 lb01 lc08 lc1001 lc1002 lstmedu lstfedu lsteco_3c lhrc04 lchna02 lchna04 lchna07 lmatb02 lmatb04 lmatb07 lengb02 lengb04 lengb07 lengb07std  lmatb02std i.schids,r


怎么固定效应出现这么多0，然后是出现太多的
note: lengb07std omitted because of collinearity
note: lmatb02std omitted because of collinearity
note: 30.schids omitted because of collinearity
note: 57.schids omitted because of collinearity
note: 65.schids omitted because of collinearity
note: 85.schids omitted because of collinearity
note: 86.schids omitted because of collinearity
note: 92.schids omitted because of collinearity