From the round-robin wikipedia
In the absence of time-sharing, or if the quanta were large relative to the sizes of the jobs, a process that produced large jobs would be favored over other processes.
Isn't that obvious? I mean if burst time of $P_1 > P_2$, then $P_1$ will remain in the running $\Longleftrightarrow$ ready state for longer time than $P_2$. What exactly does the last line mean?
