Grouped Data Mean Calculator

About this calculator

When raw data points are not available — only a frequency table grouping values into class intervals, as is common with census brackets, income surveys or exam score ranges — you cannot compute an ordinary mean directly. Instead, statisticians estimate it using the grouped mean formula, Σ(f·m) / Σf, where m is each class's midpoint (standing in for every value inside that class) and f is that class's frequency.

This is an approximation, since it assumes values are evenly spread around each class's midpoint, but it is the standard method for summarizing tabulated data in introductory statistics, and it is exactly how organizations that only publish age brackets or income brackets, rather than individual respondent data, still report an average.

Enter your class midpoints and their frequencies and this calculator computes Σ(f·m) / Σf to give you the grouped mean.