duplicates drop stock year,force
tsset stock year
gen dtcsp=D.csp_w
gen sqcsp=L.csp_w
gen xqcsp=F.csp_w
gen dttc=D.tc_w
gen dtsize=D.size_w
gen dtlev=D.lev_w
gen csp_state=csp_w*ownership
gen dtcsp_state=dtcsp*ownership
ren ownership state
save m2,replace

insheet using gdp2.csv,clear
reshape long inv,i(province) j(year)
reshape wide inv,i(province) j(year)
reshape long inv,i(province) j(year)
sort province year
save gdp2,replace

insheet using gdp1.csv,clear
sort province year
merge province year using gdp2
drop _merge

clear
use m2
sc tc_w csp_w
tabstat csp_w tc_w size_w lev_w state,s(n mean median sd min max)
tabstat csp_w tc_w size_w lev_w state,s(n mean median sd min max) by(state)
ranksum csp_w tc_w size_w lev_w, by (state)
运行结果出现了too many variables specified怎么解决