Problem
Question 7, 12.1.10 HW Score: $44.55 \%, 8.91$ of 20 points Points: 0 of 1 Save A professor had students keep track of their social interactions for a week. The number of social interactions over the week is shown in the grouped frequency distribution table to the right. Identify the upper limit of the ninth class The upper limit is $\square$ (Type a whole number) \begin{tabular}{|c|c|} \hline \begin{tabular}{c} Number of Social \\ Interactions \end{tabular} & Frequency \\ \hline 59 & 9 \\ \hline $10-14$ & 19 \\ \hline $15-19$ & 16 \\ \hline $20-24$ & 15 \\ \hline $25-29$ & 16 \\ \hline $30-34$ & 12 \\ \hline $35-39$ & 7 \\ \hline $40-44$ & 6 \\ \hline $45-49$ & 0 \\ \hline $50-54$ & 1 \\ \hline \end{tabular}
Solution
Step 1 ：The upper limit of the ninth class is the highest upper limit among all the classes.
Step 2 ：From the frequency distribution table, we can see that the classes are grouped in intervals of 5.
Step 3 ：The class with the highest upper limit is the class $50-54$.
Step 4 ：Therefore, the upper limit of the ninth class is 54.
Step 5 ：\(\boxed{54}\)
