Convoy effect is a pehnomenon associated with the first come first serve algorithm, in which the whole OS system slows down due to few slow processes.
For example: There are 3 process 
The average waiting time will be= 40/3 in case of fcfs
Now Suppose In case of Non preemptive Shortest job first scheduling there are process like this
The average waiting time here also is 13 units. Now can we say that there is convoy effect in shortest job first too ?
Please advice