Table 1.6.5. Interval Frequency Distribution
| \([a_k,b_k]\) |
\(f_k\) |
| [0,5) |
5 |
| [5,10) |
7 |
| [10,20) |
4 |
| [20,23) |
3 |
| [23,30) |
6 |
The total cummulative frequency is 25 and so
\(m = \frac{25}{2} = 12.5\) which lies in the k = 3 interval [10,20) and
\(F_2 = 12\text{.}\) Therefore
\begin{equation*}
\text{median} = (20-10) \frac{12.5-12}{4} + 10 = 11.25
\end{equation*}