What does 65 percentile mean?

Quantiles, quartiles, and percentiles


Quantiles are measures of the position of a distribution. A p-quantile indicates at which value of a distribution p% of the values ​​lie below this value.

Quartiles (Latin for "quarter values") are the quantiles at 25%, 50% and 75%. The quartile at 25% is also referred to as Q1 ("lower quartile"), that at 50% as Q2 ("middle quartile" = "median") and that at 75% as Q3 ("upper quartile"). They are one of the most frequently used form of quantiles in statistics.

Percentiles (Latin for "hundredths") divide a distribution into 100 equal parts, i.e. into 1% parts, and are therefore percentages. Percentiles divide the distribution into 1% segments - for example, the percentile corresponds P40 the point in the distribution below which 40% of all values ​​in a distribution lie.

Tips & other notes:

  • Like the median (this corresponds to the middle quartile for 50% of the individual values), quartiles are relatively stable against outliers.
  • Quantiles are measures of the position of a distribution, values ​​that are mathematically very easy to calculate and give a good overview of the relationship between an individual value of an observation and the totality of all values.