According to the diagram, 6% of the students experienced BOTH bullying and being bullied by others. This percentage is deducted to the total percentage of 36%, which comprises of the total number of students that are affected by bullying; hence, the remaining is 30%. The 30% comprises of the students that are either been bullied, or have bullied someone, but not both.

The 19.5% of 842 students is 164. In this case, there is an estimated number of 164 students who bullied another student.