In a log-log model ln(Y)=β0+β1ln(X)+ϵ\ln(Y) = \beta_0 + \beta_1 \ln(X) + \epsilonln(Y)=β0+β1ln(X)+ϵ, how is β1\beta_1β1 interpreted?
Elasticity of YYY with respect to XXX
Level change in YYY per unit change in XXX
Percentage change in YYY per unit change in XXX
Proportional change in YYY for 1% change in XXX