Forty male and forty female high school students engaged in a group decision making task in both mixed-and single-sex 4-person groups of strangers. Those subjects who participated in a mixed group were also together in a microteaching class. The study addressed three questions: (1) What are the leadership behaviors of females, and do they differ from those of males? (2) Do the behaviors and activity rates of males and females differ when they work on a task in groups with same-gender peers or in groups of mixed gender? (3) Are the behaviors of males and females working on a nonacademic group task correlated with their behaviors in a simulated classroom? The results showed no differences between the task oriented activity of males and females in single-sex groups. In mixed-sex groups whose members were unfamiliar with the task, females were less active and less influential than males. In mixed-sex groups whose members had experienced the task previously in a single-sex group, there was greater activity and influence on the part of the females. The implications of the study for educational interventions are outlined. Instructions for playing the decision making game and for carrying out the experiment are appended. (Author/JAC)