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lag is a very confusing function i try to plot lag(x,-h) and y , the results are the same figures for all the h lags. then i saw online people use lag(x,-h) as xreg in arima that won't work in my eyes if lag function is consistent, isnce it returns the same value for all the lags i don't know in which occasion people will use this function besides I suppose Lag(x,h) is the same as lag(x,-h) when doing regression, so include xreg=Lag(x,h) and xreg=lag(x,-h) in both models but the results are not the same is there anyone inter...