Right Igimoh, let's go.
Step 1: Prepare the cumulative frequency table.
To draw a cumulative frequency curve (ogive), we need the upper class boundaries and the cumulative frequencies.
The class boundaries are found by taking the midpoint between the upper limit of one class and the lower limit of the next. For example, between 19 and 20, the boundary is 19.5.
The cumulative frequency is the running total of the frequencies.
\begin{array}{|c|c|c|c|}
\hline
Mark Class & Frequency (f) & Upper Class Boundary & Cumulative Frequency (cf) \\
\hline
10-19