On each statistics page, you can see either test or production data. Set the filter at the top left:
TI uses the contents of the ISA-15 to determine whether an interchange is test or production.
Technical note
A systems person at the host can use Importer’s t parameter to force EDI data to be treated as test data, regardless of the data in the ISA-15. This affects future data being imported and is not retroactive to previously imported data.