ABSTRACT
Groups may be classied into various types. One classication is based on whether the composition of members is xed or variable. A group is called closed, when its membership remains unchanged. An example is the batch of students who graduated from the Sleepy Hollow High School in the year 2014. e other type of group, in which the membership changes from time to time, is called open. e members of the travel club Himalayan Hikers form an open group since the existing members can leave the group, and new members can join at any time. Another classication is based on the nature of communication: A group is called a peer-to-peer group when all members have equal rights and privileges in the group and members communicate with their peers to sustain the group activities. An example of an activity is the maintenance of an electronic bulletin board by the graduating students of the class of 2014 from a high school-any member could post items of common interest to be viewed by every other member of the group. In contrast, a group is called a hierarchical group, where one member is distinguished from the rest, and typically communication takes place between this distinguished member and the rest of the group. A stockbroker communicating with his clients forms a hierarchical group. Note that a hierarchical group can have multiple levels-the president of a company may want to communicate with the managers only, and each manager may communicate with the employees belonging to his or her team.
