drop L
drop if L1<1
rename L2 L-squared
label var L1 Leverage
notes L-squared L*L

estat imtest, white
reg stock L1 L2 market cash concen return
reg stock L1 L2 market cash concen return, robust
matrix list e(V)

test L1 L2
test L1=0
test L1=1
lincom L1+L2
lincom L1+L2-1
