Median mark About this question: The marks scored by 20 learners in a test were recorded as 19, 17, 19, 15, 17, 19, 22, 17, 17, 33, 17, 29, 18, 15, 19, 18, 22, and 19. (a) Prepare a frequency distribution table for the data. (b) Determine the: (i) mean mark; (ii) median mark.

The given marks are: 19, 17, 19, 15, 17, 19, 22, 17, 17, 33, 17, 29, 18, 15, 19, 18, 22, 19.
There are 18 data points.

15, 15, 17, 17, 17, 17, 17, 18, 18, 19, 19, 19, 19, 19, 22, 22, 29, 33

Since there are $n=18$ data points (an even number), the median is the average of the two middle values. These are the values at the $\frac{n}{2}$-th position and the $(\frac{n}{2} + 1)$-th position.
Position 1: $\frac{18}{2} = 9$th
Position 2: $\frac{18}{2} + 1 = 10$th

The 9th value in the sorted list is 18.
The 10th value in the sorted list is 19.
The median is the average of these two values:

The median mark is 18.5.