Grouped Data

From the grouped frequency table a) What is the class centre in the first row? b) What is the cumulative frequency at the end of the \(15\)–\(24\) class?

\[\begin{array}{ | c | c | c| } \hline \quad \text{Class} \quad & \quad \text{Class Centre} \quad & \quad \text{Frequency } \quad \\ \hline \text{5–14}& &9\\ \hline \text{15–24} & &17\\ \hline \text{25–34}& &16\\ \hline \text{35–44}& &8\\ \hline & \text{Total}& \\ \hline \end{array}\]