can ols regression be used for historical data can you use non-stationary data what is the non-stationary data when using nonstationary regression data what data to use for ols why would i use a nonstationary model ols regression how to test effect which data is considered a non-stationary time series when to use nonstationary lag what model is used to test gini coefficient of gdp in china when to use nonstationary time series is ols an autoregressive model how to test gini coefficient what is non-stationary time series data what type of model is ols regression when do we use nonstationary data how to test the effects of ols in regression if us current account balance isn't stable what model would we use when is nonstationary time series used in ols why use nonstationary data for ols regression