Statistics — Arithmetic Mean

About this lesson

This unit teaches students how to calculate the arithmetic mean (average) of a set of values and of a frequency distribution. It reviews the three measures of central tendency (arithmetic mean, median, and mode) with examples, then focuses on the arithmetic mean formula for frequency tables: x̄ = Σ(f·x) / Σf. Students learn to apply this to real-life contexts such as daily pocket money, working hours, and test scores. The unit also warns about misleading statistics, explaining that extreme values can distort the arithmetic mean, and suggests using the median or mode instead in such cases. It includes worked examples, self-evaluation questions, and exercises involving tables and bar graphs. Additionally, it introduces using Excel to compute mean, median, and mode. By the end, students should be able to calculate the arithmetic mean from raw data and frequency distributions, interpret whether a reported average is misleading, and choose a more appropriate measure of central tendency when extreme values exist.