R help - Apr 2006 - Two-way ANOVA analysis

Hi all,

I am now study ANOVA using R. Take the following data as an example.

If the factor A and B is fixed. 
I could using summary(aov(resp ~ A*B, data = mydata)) get correct ANOVA results.

However, if factor A or B is random or both factors are random, I don't know
how to get the correct ANOVA results.

Thanks in advance!

Best wishes,
Jinsong
	
----------> the data is following <-----------
resp,A,B
8.69,a,I
8.88,a,II
10.82,a,III
11.16,a,IV
8.47,a,I
8.72,a,II
10.86,a,III
11.42,a,IV
8.3,b,I
9.18,b,II
10.5,b,III
10.47,b,IV
8.74,b,I
9.54,b,II
10.92,b,III
11.13,b,IV
9.79,c,I
9.59,c,II
11.37,c,III
11.8,c,IV
9.07,c,I
9.09,c,II
10.71,c,III
10.6,c,IV