Display average of numeric fields

I'm trying to cnstruct review with CCK and nodecomment.
With CCK, I created content type 'movie', with numeric fields 'story average'
and 'sound average'.
Then, I created nodecomment named 'review' with numeric fields,'story' and 'sound'.
My users can vote score against each component with these fields in
'review'...but I can't get 'average' of each fields.
I want to display them as default value in the 'story average' and 'sound average' fields in 'movie'.
Of course, I already connected these two content type, also tried every
voting module...I could'nt find any module with score voting(not fivestar. users can vote score 1~100)
and multiple voting axis.
I also tried views_calc module, but with the module I could'nt do what I mean.

How can I do that??
I guess I have to write some PHP code.....