Mean, Median, Mode

Measure

Definition

How to Calculate

Example (Data: 2, 3, 4, 5, 6)

Use / When Useful

Effect of Extreme Values

Mean

The average of all data values.

Add all values and divide by the total number of values.

(2+3+4+5+6)/5 = 4

Best for data evenly distributed without extreme outliers.

Affected by extreme values (outliers).

Median

The middle value when data is arranged in order.

Arrange values → pick the middle one (or average of two middle values if even number).

Middle value of 2,3,4,5,6 is 4

Useful when data has outliers or is skewed.

Not affected by extreme values.

Mode

The value that occurs most often.

Identify the value(s) that appear most frequently.

All occur once → no mode

Useful for categorical or repeated data (e.g., most common rating).

Not affected by extreme values.


🔹 Quick Summary:

  • Mean = “Average” → sensitive to outliers.

  • Median = “Middle” → robust, better for skewed data.

  • Mode = “Most frequent” → good for identifying the most common value or category.