Table 3.

Zivot and Andrews (1992) Unit Root Test

Unit Root at Level 0(1)		Unit Root at First Difference 1(1)
Variables	t-statistics	t-statistics
ln HHHEx	−0.974	−5.052*
ln CO2	−0.611	−6.404*
ln EP	−1.987***	−6.504*

Note: *Refers to the level of significance at 1%, while *** refers to level of significance at 10%.