Mr. Banner has been using event recording to track how many instances of head-banging his student Bruce demonstrates during group activities. Each day, group activities vary in length. He graphs the data with the x-axis reflecting days and the y-axis the number of instances of head-banging. These data look highly variable, some days high and others low. What change should Mr. Banner make to his graph to clarify this issue? Question 4 options: Change x-axis to individual group sessions Change y-axis to rate of head-banging Change y-axis to minutes of head-banging Change nothing; sometimes data are just variable