Quantile

PrepNuggets

Quantiles are values that divide a dataset into equal parts. For example, the median is the middle quantile of a dataset, dividing it into two equal parts. The first quartile is the lower quantile, dividing the dataset into the bottom 25% and top 75%, while the third quartile is the upper quantile, dividing the dataset into the bottom 75% and top 25%.

You can also use quantiles to divide a dataset into more than just two or four parts. For example, the deciles divide a dataset into 10 equal parts, while the percentiles divide a dataset into 100 equal parts.

Quantiles are a useful way to summarize and describe the distribution of a dataset, particularly when comparing the distribution of data between different groups or conditions. For example, if you want to compare the distribution of heights between two groups of people, you could use quantiles to determine whether one group is taller or shorter than the other.

Quantiles can be visualised with a box and whisker plot.

Specialised quantiles:

  • Median
  • Quartile
  • Quintile
  • Decile
  • Percentile
Synonyms:
Fractile