Empirical Relationship
The empirical relationship in statistics is a mathematical formula that connects the three measures of central tendency: mean, median, and mode. For a moderately skewed distribution, it states that the mode is equal to three times the median minus two times the mean.
Key Concepts
It provides a quick and reliable way to estimate one measure of central tendency if the exact values of the other two are known.
This relationship holds true primarily for moderately skewed or asymmetrical frequency distributions.
In a perfectly symmetrical distribution, the mean, median, and mode are all exactly equal, which perfectly satisfies this empirical equation.
Real World Applications
Estimating the most common household income (mode) in a city when the average income (mean) and the middle income value (median) are already calculated from census data.
Quickly finding the median test score of a large classroom when a teacher only has the average score and the most frequent score readily available.