sequence

ADF test value

Significant level

P value

Stationarity

1%

5%

10%

CPI

0.066846

−2.584539

−1.943540

−1.614941

0.7022

Non-stable

PPI

−0.707841

−2.583011

−1.943324

−1.615075

0.4084

Non-stable

DCPI

−6.427866

−2.584539

−1.943540

−1.614941

0.0000

smooth

DPPI

−4.920177

−2.583011

−1.943324

−1.615075

0.0000

smooth