Median
The middle value of all data points
Definition:
12.5
11.9
12.5
12.7
12.7
12.9
13.0
13.2
13.4
13.5
In our data it lies between the 5th and 6th data points
Median = 12.9 – 12.7
                       2
Median = ± 0.1
Median = 12.9 - 0.1 = 12.8
Median = 12.7 + 0.1 = 12.8
or