Since I can't physically insert the appropriate heading, with units, I'll make the data table below by using the information given. 
Disk-----------Measurement of ZOI (mm)   also acceptable is ZOI (mm) 
A--------------13 ( +/- 2 mm) 
B--------------8
C-------------0
D-------------9 
        
             
        
        
        
Hold on I can help you with this it's gonna take me maybe 10-20 min