Answer:
Frequency
Step-by-step explanation:
A good operational definition of the dependent variable in an experiment designed for this would be Frequency. This ultimately means the number of occurrences of a repeating event per unit of time. Therefore in this scenario the more times that student participation increases for a specific number of chairs in the classroom needs to be added and then compared to the different amount of chairs in order to see which amount of chairs actually causes the most student participation.