Hill et al. (2007) examined whether providing children with a leaflet based on the ‘theory of planned behaviour’ increased their exercise. There were four different interventions (intervention): a control group, a leaflet, a leaflet and quiz, and a leaflet and a plan. A total of 503 children from 22 different classrooms were sampled (classroom). The 22 classrooms were randomly assigned to the four different conditions. Children were asked ‘On average over the last three weeks, I have exercised energetically for at least 30 minutes ______ times per week’ after the intervention (post_ exercise). Run a multilevel model analysis on these data (hill_2007.sav) to see whether the intervention affected the children’s exercise levels (the hierarchy is children within classrooms within interventions).