[R] factorial anova

From: Petra Wallem <pwallem_at_bio.puc.cl>
Date: Mon 26 Dec 2005 - 13:01:29 EST

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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https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html Received on Mon Dec 26 13:13:44 2005

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