What is Mode?
The mode is the value that appears most frequently in a dataset. A dataset can have one mode (unimodal), two modes (bimodal), multiple modes (multimodal), or no mode if all values appear equally.
Mode = value(s) that appear most frequently
In {1, 2, 2, 3, 4}: Mode = 2 (appears twice)
In {1, 2, 2, 3, 4}: Mode = 2 (appears twice)
Types of Mode
- Unimodal: One mode (e.g., 1, 2, 2, 3 → mode = 2)
- Bimodal: Two modes (e.g., 1, 1, 2, 2, 3 → modes = 1 and 2)
- Multimodal: Three or more modes
- No mode: All values appear the same number of times
Mode Examples: Unimodal, Bimodal, Multimodal
| Dataset | Mode | Type |
|---|---|---|
| {1, 2, 2, 3, 4} | 2 | Unimodal |
| {1, 1, 2, 2, 3} | 1 and 2 | Bimodal |
| {1, 1, 2, 2, 3, 3} | 1, 2, and 3 | Multimodal |
| {2, 4, 6, 8, 10} | None | No mode |
| {5, 5, 5, 5} | 5 | All same |
Mode for Categorical Data
Unlike mean and median, mode is the only measure of central tendency that works with categorical (non-numerical) data:
Colors: {Red, Blue, Red, Green, Red, Blue}
Mode = Red (appears 3 times)
Shoe sizes: {7, 8, 8, 9, 10, 8, 7}
Mode = 8 (most common size to stock)
Mode = Red (appears 3 times)
Shoe sizes: {7, 8, 8, 9, 10, 8, 7}
Mode = 8 (most common size to stock)
Mode in Normal Distribution
In a perfectly normal (bell-shaped) distribution, mean = median = mode. They are all equal and located at the peak of the curve. When they diverge, it indicates skewness in the data.
Real-World Uses of Mode
- Retail inventory: Stock the most popular (modal) size, colour, or style
- Manufacturing: Quality control — most common defect type (modal defect)
- Weather: Modal weather type for a season (most frequently occurring)
- Survey analysis: Most common response to a multiple-choice question
- Transportation: Peak traffic hours (modal commute time)