The data by Vickers et al. (1981) are stored in a list named vickers
and represent three different social relations among 29 seventh grade students, 12 boys and 17 girls, in a school in Victoria, Australia. Each student was asked if
Network 1: he\ she got on with another given student;
Network 2: he\ she considered another given student as his\ her best friend;
Network 3: he\ she would have liked to work with another given student.
The matrix sex
is an edge-specific binary covariate recording the gender of pairs of students. If a pair of students is of the same sex, the corresponding entry in the matrix is 0, otherwise is 1.