Relative position of mean, median and mode
Topic: Economic Data: Census, NSS, Surveys and Statistical Tools · NCERT: Class 11, Ch 5 "Measures of Central Tendency"
Meaning
The relative position of the mean, median and mode depends on the shape of the distribution.
- In a symmetric distribution, where both sides mirror each other, all three are equal.
- In a moderately skewed distribution, which has one peak and a tail stretched to one side, the median usually lies between the mean and the mode. Karl Pearson's rule links the three: Mode ≈ 3 Median − 2 Mean.
This rule holds only for moderately skewed data with a single peak. It is not true for every distribution.
Example
Income is right-skewed: most people earn modest amounts, and a few earn very large amounts. So mean > median > mode, because the rich pull the mean upward. This is why per capita income overstates what a typical Indian earns, and why the median is the better guide.
Don't confuse with
- "Median always lies between mean and mode": this is not always true. It holds only for moderately skewed data with a single peak.
Related concepts
- Measures of central tendency
- Arithmetic mean
- Weighted arithmetic mean
- Median
- Quartiles
- Decile
- Percentiles
- Mode
- Bimodal and multimodal distribution
- Modal class