Hardy Weinberg law - (Feb/07/2006 )

hi everyone. I would like to ask how do they compute'use the hardy wienberg law for genotype screening of Positive and Null alleles of a certain gene?

I am familiar with the p2+2pg+q2 or p+q=1 but i dont know how to approach it. How to get the expected frequency for chi-squaretest eventually.

sorry but hope you can help me. thanks

Please, rina77, could you be more precise?

I can't understand if your problem is about application or theory: do you have to solve some kind of school test, showing how to get to an expected result? or do you understand the law but can't apply it?
Sorry, but I couldn't understand...