#Minitab regression series
I need to overcome the Autocorrelation problem in this time series and analise the Durbin-Watson test to check the autocorrelation. However I am not really sure if I am doing this in the right way as I cannot find any example using this kind of data. (If I include Difft I receive the following message: * ERROR * Continuous predictors must have more than one distinct value.)Īlso I do not include the constant term, as I think that doing first difference we should force the Regression through the origin.Īnalyzing the results after fixing the Autocorrelation problem the Durbin test shows a negative autocorrelation. Then I run a normal regression analysis selecting DiffY, DiffQrt1, DiffQrt2 and DiffQrt3 and do not select the Difft as it is the trend and the values are always 1. I also saw that applying this method to overcome autocorrelation will give a stationary process, which I think that we are removing Trend and seasonality The results presented for best subsets, by default in Minitab. I have some examples but none use Dummy variables. It compares all possible models that can be created based upon an identified set of predictors. I am trying to overcome the autocorrelation problem and I found that I could use first difference. $Revenue= \beta_0+\beta_1+\beta_2(Qrt1)+\beta_3(Qrt2) + \beta_4(Qrt3)$īecause it is a Time series data, autocorrelation is a problem.
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