Average (Mean)

Definition

An Average (specifically the arithmetic mean) is a single number taken as representative of a list of numbers. It is calculated by dividing the total sum of all the values in a set by the number of values in that set.

Why It Matters

Averages are used everywhere to summarize large datasets. Whether it's a student's GPA, the average temperature for a month, or the average cost of a home in a specific city, averages allow us to digest complex data quickly.

The Flaw of Averages

While useful, an average can be highly skewed by outliers (extreme highs or lows). For example, if nine people in a room earn $50,000 a year, and one person earns $10 million, the "average" salary in the room is over $1 million. In cases with extreme outliers, looking at the median (the literal middle number) often provides a more accurate picture of reality.

Practical Example