How can include/exclude fields in calculation ?

Hello,

I got a question.

I have 8 fields which could be ted from 1 to 6 and if they could not be rated for certain circumstances it would get the value of x.

I wanat to calculate the avarage of rated parameters.

When I use the "average" function in calculation the number of enetered information would be fixed. That means if all parameters are rated the result is ok but if a parameter could not be rated it ruines my calculation (while the number of species are fixed in this case 8).

Isthere any solution for my problem? such if a value is not zero it counts otherwise should be negelcted.

Please help me.

BR