The QC Analyst reviewing the data for Group 4, discovered that the cells died, including those in the control media, indicating an issue unrelated to the media being tested. This violated the QC criteria, so the run was marked "Reviewed - Rejected", and is excluded from the final analysis.
The number of replicate samples per media is shown here: Number of Replicates
Fine-grained permissions are available corresponding to different roles in a Lab organization, such as "QC Analyst", for setting quality control states. Administrators also have the option to hide data based on QC state -- not done here so that you can browse all the data.