The table shows the numbers of cases of Corona Virus registered in Uganda between March, 2020 and June, 2021. Draw a frequency distribution table, a graph of cumulative frequencies, and estimate the median.

Add the frequencies:

Total cases, $N = 81$.

The median is the $\frac{N+1}{2}$th value:

The 41st case.

Classes: $0-9$, $10-19$, $20-29$, $30-39$, $40-49$, $50-59$, $60-69$, $70-79$, $80+$.
Upper boundaries: 10, 20, 30, 40, 50, 60, 70, 80, 90.

Plot points: $(10,14)$, $(20,29)$, $(30,49)$, $(40,63)$, $(50,72)$, $(60,77)$, $(70,79)$, $(80,80)$, $(90,81)$.
Join with straight lines.

Draw horizontal line at cf $= 41$.
It intersects the line segment from $(20, 29)$ to $(30, 49)$.

Formula for intersection:

where $L = 20$ (upper boundary of previous class),
$M = 41$ (median position),
$\text{cf}_{prev} = 29$,
$\text{cf} - \text{cf}_{prev} = 49 - 29 = 20$,
$w = 30 - 20 = 10$ (class width).

Substitute:

(c) Explanation: The ogive is plotted with cumulative frequencies against upper class boundaries. The horizontal line at cf $= 41$ intersects the ogive between upper boundaries 20 and 30. The x-coordinate of the intersection gives the estimated median of 26 cases.

26