In a large scale newspaper experiment 5,132 readers of the German weekly, Die Zeit, participated in a three-person bargaining game. In our data analysis we focus on (1) the influence of age, gender, profession and the medium chosen for participation on bargaining behavior and on (2) the external validity of student behavior (inside and outside the lab). We find that older participants and women care more about equal distributions and that Internet users are more self-regarding than those using mail or fax. Decisions made by students in the lab are rather similar to those made by students in the newspaper experiment. Furthermore, student behavior is not different from non-student behavior when the same age group is considered, indicating a high degree of external validity of student data.