Dr. Rаmоs wаs interested in hоw different interventiоns support sociаl functioning in children with autism. She also wondered whether children’s language abilities influence how effective different therapies are. Dr. Ramos recruited children diagnosed with autism and randomly assigned them to either an Applied Behavior Analysis (ABA) program, or a Social Skills Group program. Within each of these intervention groups, some children were minimally verbal while others had fluent language. After 12 weeks of an intervention program, all children participated in a structured recess simulation, and the number of spontaneous peer social initiations was recorded. A higher number of initiations was considered an indication of better social functioning. The results are shown below. In the study described above, how many independent variables are there?