This document provides information on calculating the median of grouped and ungrouped data. It defines median as the middle value of an ordered data set. For ungrouped odd-sized data, the median is the middle number. For even-sized data, the median is the average of the two middle numbers. For grouped data, the median is calculated by ordering the class boundaries and frequencies, calculating the cumulative frequency, and finding the class where the cumulative frequency equals or exceeds half the total frequency. Several examples are provided to demonstrate calculating the median for different data sets.