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    Post hoc comparisons. How to do the grouping?

    Hi all, Can anyone help me trying to understand how to do the grouping at the end of the post-hoc procedure in the one way ANOVA? For each kind of test (LSD, Bonferroni, Tukey, Scheffé etc) I can understand the way it calculates the confidence interval and how it check if the means of each...
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    Variable selection in multiple regression based on regression itself results

    Hi everybody, I have a question relative to the multiple linear regression. Here is the case: Y=dip var x1, x2, x3= indip var suppose that I have no collinearity between x1, x2 and x3 If I find x1 not statistically significant (p-value>alfa), can I remove x1 from my analysis and run the...
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    ANOVA, residual normality assumptions

    Hi everybody, I would like to ask you something about the normality hypotesis on the residuals when performing an ANOVA. Do I have to check the entire residuals data set or, do I have to check normality of the residuals relative to each level of each IV (for example, 1 IV with 3 levels, 3...
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    ANOVA One-way Vs Factorial ANOVA. Discordant results.

    Hi everybody, I have to investigate the influence of many categorical factors (A,B,C) on a continuous response variable (Y). The procedure I'm following is: 1) Make three One-way ANOVA, every time with a different predicotor A, B, C) 2) Make all the three possible ANOVA two-way using the...
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    ANOVA One-way Vs Factorial ANOVA. Discordant results. Help

    Hi everybody, I have to investigate the influence of many categorical factors (A,B,C) on a continuous response variable (Y). The procedure I'm following is: 1) Make three One-way ANOVA, every time with a different predicotor A, B, C) 2) Make all the three possible ANOVA two-way using the...