Answer:
to calculate the median:
1) we arrange the series in ascending order
6 7 7 8 10 14 15
2) 7 values, odd series
the median separates the series into 2 series of the same value
Determine the rank of the median
Add 1 to the total count, then divide the result by 2.
The number obtained corresponds to the rank of the median within the statistical series.
(7+1)/2=4; the median is the 4th value, i.e. 8