Decile
In descriptive statistics, a decile is any of the nine values that divide the sorted data into ten equal parts, so that each part represents 1/10 of the sample or population. A decile is one possible form of a quantile; others include the quartile and percentile. A decile rank arranges the data in order from lowest to highest and is done on a scale of one to ten where each successive number corresponds to an increase of 10 percentage points. Special Usage: The decile mean

A moderately robust measure of central tendency - known as the decile mean - can be computed by making use of a sample's deciles  to  ( = 10th percentile,  = 20th percentile and so on). It is calculated as follows:

 

Apart from serving as an alternative for the mean and the truncated mean, it also forms the basis for robust measures of skewness and kurtosis, and even a normality test. See also
 Summary statistics
 Socio-economic decile (for New Zealand schools)

References

Summary statistics

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