Different stationarity tests

The order of differencing

The test statistic values

p-value

ADF

0

−4.2998

0.01

PP

0

−11.270

0.01

KPSS

0

0.64742

0.02

ADF

1

−7.305

0.01

PP

1

−28.292

0.01

KPSS

1

0.012779

0.10