Knowing that a process is already stationary (i.e. I(0) and ADF test for presence of unit root has been rejected), is there any need to check the first difference? If yes, what is the rationale/application of it?
Any help is appreciated.
Knowing that a process is already stationary (i.e. I(0) and ADF test for presence of unit root has been rejected), is there any need to check the first difference? If yes, what is the rationale/application of it?
Any help is appreciated.