“…Another prominent approach is the "augmented Dickey-Fuller test" (ADF) (Gujarati, 2003). But, according to Stadnytska (2010), ADF inflates the actual significance level, and a correction for such effect leads to moderate statistical powers. Also, a method conventionally used for testing the null hypothesis of deterministic stationary trend, versus the alternative of a stochastic trend, is the test proposed by Hobijn, Franses, and Ooms (2004), and generalized by Kwiatkowski, Phillips, Schmidt, and Shin (1992), called KPSS, which has been extensively used in many fields (Chen & Pun, 2019;Montasser, 2015).…”