Median

Median is the middle observation in a group that has been ordered in either ascending or descending order.

For odd-numbered group, median is at (n+1)/2th position;
For even numbered group, median is the average of n/2th and (n+1)/2th positions


Median = L +[ (n/2-CF)/f]i

Where:
L = lower limit of class containing the median;
CF = cumulative frequency preceding the median class;
f = frequency of observations in the median class;
i = class interval of median class