tabulate state, generate(d)
reg allmort  beertax d1-d48, noconstant
reg allmort beertax d2-d48, vce(hc3)
testparm d*

xi: regress allmort beertax i.state, vce(hc3)
testparm _Istate*
 
xi: regress allmort beertax i.state, vce(cluster state)

xtreg allmort beertax, fe vce(cluster state)