Atypical group must have the following essential characteristics in order to be called a group in the psychological sense. 1. Leadership - According to Carter, a leader is a person who is able to lead the group towards the attainment of the goal. The teacher helps the students in the attainment of the goals. In that sense, the teacher is the leader of the classroom group. 2. Interdependency/ Common Interest - The members of a group have common and well defined goals, interest and ideals. Every member tries to attain the goals set down by the society e.g. members of rotary club have a common aim of social work for the benefit of underprivileged. The behavior of one member of a group influences that of the other and in this way his own behavior is influenced. This type of relationship is also known as psychological relationship.