Climate Change Impacts on Winter Wheat Yield in Northern China

Table 1

Unit root test and cointegration test.

	lnY	lnF	lnM	lnL	lnI	lnT	lnP
LLC	−5.73	−8.08	−4.21	−1.63	−0.30	−6.48	−7.28
				−11.28	−10.33
ADF	48.25	47.05	18.24	12.22	7.23	77.30	79.58
				94.82	86.39
Cointegration Test
ADF	−6.78^a

, , and represent that the null hypothesis of nonstationary is rejected at 10%, 5%, and 1% level, respectively. When there are two statistics in a cell, the top number is for the test on the original variable, and the bottom number is for the test on the variable after it has been differenced once. ^a represents that the null hypothesis of no cointegration is rejected at 1% level.