Text-based stimulus: Stacked bar chart titled Homework score completeness by period. Four bars labeled Period 1 through Period 4, each split into complete and missing portions. Missing portions are 2%, 3%, 22%, and 2% respectively; Period 3 missing segment is visibly larger. The accompanying stacked bar chart shows missing homework scores by class period. Period 1 has 2% missing, Period 2 has 3%, Period 3 has 22%, and Period 4 has 2%. What is the best next step?