  Round Robin (RR) Scheduling is the basis of time sharing environment. It is
the combination of First Come First Served (FCFS) scheduling algorithm and
preemption among processes. It is basically used in a time sharing operating
system. It switches from one process to another process in a time interval. The
time interval or Time Quantum (TQ) is fixed for all available processes. So,
the larger process suffers from Context Switches (CS). To increase efficiency,
we have to select different TQ for processes. The main objective of RR is to
reduce the CS, maximize the utilization of CPU and minimize the turn around and
the waiting time. In this paper, we have considered different TQ for a group of
processes. It reduces CS as well as enhancing the performance of RR algorithm.
TQ can be calculated using min-max dispersion measure. Our experimental
analysis shows that Group Based Time Quantum (GBTQ) RR algorithm performs
better than existing RR algorithm with respect to Average Turn Around Time
(ATAT), Average Waiting Time (AWT) and CS.
