Using it's concept, it is found that the median number of posts made was of 8.5.
What is the median of a data-set?
The median of the data-set separates the bottom half from the upper half, that is, it is the 50th percentile.
In this problem, the total number of observations is the sum of the frequencies, hence:
T = 1 + 0 + 3 + 1 + 2 + 1 + 1 + 2 + 3 + 5 + 9 = 28
Even number, hence the median is the mean between the 14th and the 15th elements, of the ordered set, hence:
M = (8 + 9)/2 = 8.5.
To remind, the ordered set is: {0, 1, 1, 1, ..., 8, 8, 8, 9, 9, 9, 9, 9, 10, 10, 10, 10, 10, 10, 10, 10, 10}
The median number of posts made was of 8.5.
You can learn more about the median at https://brainly.com/question/16103295