This document discusses different methods for calculating the mean or average of data. It defines the mean as the central value of a set of numbers used to measure central tendency. Formulas are provided to find the mean of individual data points by summing the values and dividing by the number of data points. The document also discusses finding the mean of grouped data, which involves using a frequency table with class midpoints and frequencies to calculate the weighted average. Examples are provided to demonstrate both individual and grouped data means.