I would like to test hypotheses like the following example: Effect A is weaker than effect B.

For Effects A and B, I have a 2 (error: present vs. absent) x 2 (group: control vs. experimental) contingency table, thus getting chi and e.g. a phi-coefficient.

My question is: How can I find out whether the resulting effect A is stronger than B?

I'll be grateful for any help!

Thanks for your consideration