I took bacteria samples at 30 grocery stores. Each grocery store was tested for 3 different bacteria types. I then taught a foodborne illness class to the managers of the grocery stores. After teaching this class I re-sampled the areas at each grocery store for the 3 types of bacteria. I want to test if the foodborne illness class reduced the presence of the bacteria (which is measured as positive or negative).
Below is an example of my data set. I read the Chi-Square can be good for answering a question similar to this. But I'm a little confused because each participant (i.e., grocery store) has 3 bacteria tests. So I don't know how to run a test on this. Any help would be greatly appreciated.
I just made up the data on the following table. But the real data set looks the same with 30 groceries instead of 3.