Hi,

I'm trying to run a chi square test to compare two different screening methods for a pathogen. I'm testing this by diluting a known positive in a 10-fold dilution series and running those through two different screening methods. The way I'm setting up the chi square test is by using replicates as rows (3 reps, 3 rows) and the methods as columns (method 1, method 2). So I have 3 rows and 2 columns. For the observed values I'm using the endpoint detection (ex: if I ran 5 dilutions and was able to detect pathogen using one method as far as the 4th dilution in the first replicate then I used the number 4 as the observed value for that cell).

Does this make sense? Is there a better way to set up the table? The only other way I can think of to do it would be to use the number of times each method picks up sample at a certain dilution, but I'm not really sure how I'd organize that in the table.

I hope that makes sense.