A contingency table might be useful. See
Contingency table - Wikipedia, the free encyclopedia
Hi, to whom might help me!
... and I really need help with this one! I've been strugling with this for days now. I just can't get it right..
Background: I want to show that osteoarthritis is a symmetric disease. One pathological finding is an Osteophyte, an abnormality in the joint. You can have this in both knees, hips, hands etc.
I want to show that there is an assosiation of having an Osteophyte in two opposite finger joint - if you have it in your left thumb, you probably have it in your right and vica verca. In the same way, if you don't have it in one joint, you often don't have it in the opposite.
I.e: That this is a symmetric thing, that there is an interrelationship.
This is my findings:
(OP = the pathology, an osteophyte)
OP both right and left joint: 849 subjects
OP in either right or left joint: 750 subjects
OP only in right joint: 163 subjects
OP only in left joint: 110 subjects
I guess the top two support my hypothesis, while the bottom two do not. Some articles I've read talk about Odds Ratio, which kind of make sence.. But I'm not sure.. I've found an odds ratio of 35,5 for my data, but I don't know if its correct to present it this way.