Tests for Unit-Root versus Threshold Specification With an Application to the Purchasing Power Parity Relationship
单位根与阈值设定的检验:购买力平价关系的应用
We consider modeling the real exchange rate by a stationary three-regime self-exciting threshold autoregressive (SETAR) model with possibly a unit root in the middle regime. This representation is consistent with purchasing power parity in the presence of trading costs. Our main contribution is to provide statistical tools for testing unit root versus a SETAR. First, we show that a SETAR with a unit root in the middle regime is stationary and mixing under reasonable…