I want to compare the difference in sample type and diagnostic categories in two different time frames .. the data has nominal and ordinal values only.. which test is to be used .. pls suggest
To find the association between categorical variables, Pearson Chi square test. If >20 % of the cell value after tabulation is less than 5, then Fisher's Exact test should be done.
Again, if needed to see the prediction by RR or OR, one has to go for regression analysis.