Tahirawan77
Involved In Discussions
Hi,
I have a Response variable Y which consist of 'count of events' on monthly basis.
I have 7 Predictor variables: X1 ...X7 (All are counts)
First I performed a uni-variant analysis by using Minitab 'Fitted line plot' for each X vs Y. (Although it is not statistically correct as Fitted line plot requires Continuous response variable). But X1, X4, X6 & X7 were identified as statistically significant predictors. See detail graphs attached
Next I performed a 'Poisson Regression' using Minitab. I used 'Backward elimination' method with 0.05 as 'Alpha to remove'. I got X2, X4 and X7 as statistically significant factors. See results attached.
Next I again performed a 'Poisson Regression' using Minitab. Again I used 'Backward elimination' method but this time I used 0.1 as 'Alpha to remove'. I got X1, X2, X5 and X7 as statistically significant factors. See results attached.
My questions is in my first Poisson regression analysis., why X1 & X6 were not identified as statistically significant as they were identified earlier in the Fitted Line Plot. Further X2 was not statistically significant on Fitted line plot but became significant in the Poisson regression?
Second question is why big difference between the two Poisson regression results.
Thanks
I have a Response variable Y which consist of 'count of events' on monthly basis.
I have 7 Predictor variables: X1 ...X7 (All are counts)
First I performed a uni-variant analysis by using Minitab 'Fitted line plot' for each X vs Y. (Although it is not statistically correct as Fitted line plot requires Continuous response variable). But X1, X4, X6 & X7 were identified as statistically significant predictors. See detail graphs attached
Next I performed a 'Poisson Regression' using Minitab. I used 'Backward elimination' method with 0.05 as 'Alpha to remove'. I got X2, X4 and X7 as statistically significant factors. See results attached.
Next I again performed a 'Poisson Regression' using Minitab. Again I used 'Backward elimination' method but this time I used 0.1 as 'Alpha to remove'. I got X1, X2, X5 and X7 as statistically significant factors. See results attached.
My questions is in my first Poisson regression analysis., why X1 & X6 were not identified as statistically significant as they were identified earlier in the Fitted Line Plot. Further X2 was not statistically significant on Fitted line plot but became significant in the Poisson regression?
Second question is why big difference between the two Poisson regression results.
Thanks
Attachments
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Y vs X1.JPG45.6 KB · Views: 6
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Y vs X2.JPG44.7 KB · Views: 6
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Y vs X3.JPG42.1 KB · Views: 4
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Y vs X4.JPG44.6 KB · Views: 2
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Y vs X5.JPG42.8 KB · Views: 7
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Y vs X6.JPG42.3 KB · Views: 4
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Y vs X7.JPG47.1 KB · Views: 11
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Poisson regression Alpha 0.05.JPG51.3 KB · Views: 8
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Poisson regression Alpha 0.1.JPG61.6 KB · Views: 9