请教各位，循环语句为什么一直提示no observations  r(2000);是哪里写错了吗？ 谢谢

forvalues i=1(1)432{
reg lnauditfee size recratio invratio big4 opinion roe tobinq lratio deratio epsinc salesinc loss soe add if group_id==`i',noc
gen  b_size=_b[size] if group_id==`i'
gen  b_recratio=_b[recratio] if group_id==`i'
gen  b_invratio=_b[invratio] if group_id==`i'
gen  b_big4=_b[big4] if group_id==`i'
gen  b_opinion=_b[opinion] if group_id==`i'
gen  b_roe=_b[roe] if group_id==`i'
gen  b_tobinq=_b[tobinq] if group_id==`i'
gen  b_lratio=_b[lratio] if group_id==`i'
gen  b_deratio=_b[deratio] if group_id==`i'
gen  b_epsinc=_b[epsinc] if group_id==`i'
gen  b_salesinc=_b[salesinc] if group_id==`i'
gen  b_loss=_b[loss] if group_id==`i'
gen  b_soe=_b[soe] if group_id==`i'
gen  b_add=_b[add] if group_id==`i'
replace lnauditfee_p=b_size*size+b_recratio*recratio+b_invratio*invratio+b_big4*big4+b_opinion*opinion+b_roe*roe+ ///
b_tobinq*tobinq+b_lratio*lratio+b_deratio*deratio+b_epsinc*epsinc+b_salesinc*salesinc+b_loss*loss+b_soe*soe+b_add*add if group_id==`i'
}  

no observations
r(2000);