[R] how to extract the effect size eta in an anova table

[Martin Batholdy]

Hi,

perhaps the question I have is more a statistical question than a  
question about R.
But I hope nevertheless  someone could help me.


If I have the following anova table;

Analysis of Variance Table

Response: aktiv
                      			Df  Sum Sq Mean Sq F value   Pr(>F)
fac1             		1  		0.1091  0.1091  1.1207 0.291156
fac2                		1  		0.2035  0.2035  2.0903 0.149935
fac3            		1  		0.9400  0.9400  9.6568 0.002186 **
fac4          		1  		0.2338  0.2338  2.4018 0.122912
fac1:fac2      		1  		0.0273  0.0273  0.2809 0.596754
fac1:fac3      		1 		0.0528  0.0528  0.5426 0.462309
fac2:fac3   	        1  		0.0122  0.0122  0.1252 0.723902
Residuals          184 	        17.910  0.0973

How do I compute eta^2 for factor 3 (fac3)?

Can I just calculate it over the sum squares?
Like 0.9400 / (0.1091 + 0.2035 + 0.9400 .... + 0.0122 + 17.910);
  is that my eta^2?


How would I report the results?
(Like F(1,184) = 9.65 ..?)
(don't you have always two degrees of freedom in an Anova?)



thanks for any help!