
Dear all,
I have 3 models (from simple to complex) and I want to compare them in order to 
see if they fit equally well or not.
From the R prompt I am not able to see where I can get this information.
Let´s do an example:

fit1<- lm(response ~ stimulus + condition + stimulus:condition,  data=scrd) 
#EQUIVALE A lm(response ~ stimulus*condition, data=scrd) 


fit2<- lm(response ~ stimulus + condition, data=scrd) 

fit3<- lm(response ~ condition, data=scrd) 


> anova(fit2, fit1) #compare models 
Analysis of Variance Table

Model 1: response ~ stimulus + condition
Model 2: response ~ stimulus + condition + stimulus:condition
  Res.Df    RSS Df Sum of Sq      F Pr(>F)
1    165 364.13                           
2    159 362.67  6    1.4650 0.1071 0.9955


> anova(fit3, fit2, fit1) #compare models 
Analysis of Variance Table

Model 1: response ~ condition
Model 2: response ~ stimulus + condition
Model 3: response ~ stimulus + condition + stimulus:condition
  Res.Df    RSS Df Sum of Sq      F Pr(>F)
1    171 382.78                           
2    165 364.13  6    18.650 1.3628 0.2328
3    159 362.67  6     1.465 0.1071 0.9955



How can I understand that the simple model fits as good as the complex model 
(the one with the interaction)?

Thanks in advance

All the best


      
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