when is spurious time series regression spurious test definition spurious time series spurious regression definition when does spuriousness occur spurious regression definition spurious regression definition when does spuriousness occur define spurious regression and why when does spurious regression occur spurious regression definition spurious time series when do spurious time series occur spurious regression definition why does spurious regression occur spurious regression is it when the two time series are cointegrated? spurious regression spurious regression definition spurious time series definition spurious regression definition