[R] factorial anova

[Rick Bilonick]

On Sun, 2005-12-25 at 23:01 -0300, Petra Wallem wrote:
> Hello  every body, I am trying to do a factorial anova analysis
> following this model:
> 
> model<-anova(lm(responsevariable~factorA*factorB))
> model<-anova(lm(luz$dosel~luz$estado*luz$Bosque))
> 
>  Df Sum Sq Mean Sq F value    Pr(>F)
> estado         1 6931.1  6931.1 41.6455 7.974e-06 ***
> Bosque         1   36.6    36.6  0.2197    0.6456
> estado:Bosque  1   36.6    36.6  0.2197    0.6456
> Residuals     16 2662.9   166.4
> 
> Strange is that the sum of squares of the factor Bosque are identical to
> the SS of the interaction, and are non significant. But when I plot the
> data, the interaction surley is significant...
> 
> my data.frame looks as follows:
> 
> Bosque   estado      lux  dosel
> 1   deciduo pristino  703 88.56
> 2   deciduo pristino  800 90.64
> 3   deciduo pristino  150 95.84
> 4   deciduo pristino  245 87.52
> 5   deciduo pristino 1300 91.68
> 6   deciduo   activo 1900 26.16
> 7   deciduo   activo  840 59.44
> 8   deciduo   activo  323 69.84
> 9   deciduo   activo  112 75.04
> 10  deciduo   activo 1360 51.12
> 11 siemprev   activo  900 41.76
> 12 siemprev   activo  480 65.68
> 13 siemprev   activo  350 78.16
> 14 siemprev   activo  350 37.60
> 15 siemprev   activo  272 58.40
> 16 siemprev pristino  100 94.80
> 17 siemprev pristino   60 95.84
> 18 siemprev pristino   50 97.92
> 19 siemprev pristino  270 94.80
> 20 siemprev pristino  110 97.92
> 
> Dose some body understand what I am doing wrong??? I have been
> navigating at the R site search, but didn't found much posting on
> factorial anova.
> 
> In advance thanks a lot for your comments
> Petra
> 
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It would help if you would use the "dump" function and paste the output
into an e-mail:

> dump("luz","")

Also, it's much easier to use "data=luz" as an argument in the lm
function rather than appending the data frame name to each variable. I
don't think that "model" contains the lm model output. It looks like you
are saving the anova table.