What are Mean, Median, Mode, and Range?

In statistics, Mean, Median, and Mode are known as "Measures of Central Tendency". They are different mathematical methods used to find the center or typical value of a dataset. Range, on the other hand, is a "Measure of Dispersion" that tells you how spread out the numbers are.

1. Mean (The Average)

The Mean is what most people think of when they hear the word "average". To find the mean, you add up all the numbers in the dataset and divide the total sum by the count of numbers.
Example: For data (2, 4, 6), Sum = 12. Count = 3. Mean = 12 / 3 = 4.

2. Median (The Middle Value)

The Median is the exact middle number in a sorted, ascending list of numbers. If the dataset has an odd amount of numbers, the median is the center value. If it has an even amount, you take the two middle numbers and find their average.
Why use it? The median is highly useful when a dataset has extreme outliers (like calculating average incomes) because it doesn't get skewed by a single massive number.

3. Mode (The Most Frequent)

The Mode is the number that appears most frequently in your dataset. A dataset can have one mode (unimodal), two modes (bimodal), multiple modes, or no mode at all if every number appears exactly once.

4. Range (The Data Spread)

The Range is the difference between the highest value and the lowest value in the dataset. It gives a quick, basic understanding of how far apart the numbers are. Formula: Max Value - Min Value.

Real-World Uses in Data Science

These four formulas form the foundation of Descriptive Statistics and Machine Learning. E-commerce sites use the Mode to find the most commonly bought shoe size. Real estate agents use the Median to report house prices so million-dollar mansions don't skew the data. Meteorologists use the Mean to calculate average monthly temperatures.