what tests take into account the univariate regression which test is non stationary does granger cause univariate regression can you use first differences for granger causality test why use first difference what tests do you use to test non stationary sentiment when does sentiment test work for univariate is sentiment non-stationary is sentiment stationary is sentiment non-stationar how to use dfgls on sentiment panel when to apply first difference for sentiment when a sentiment index is non stationary which test is performed? when evaluating sentiment in a granger sample is the first difference stationary how to test the nonstationarity of sentiment which statement is true for sentiment? are first differences considered non stationary when using the first difference is sentiment non-stationary when to use first difference does sentiment show non static