Percentile

The n^th percentile of an observation variable is the value that cuts off the first n percent of the data values when it is sorted in ascending order.

Problem

Find the 32^nd, 57^th and 98^th percentiles of the eruption durations in the data set faithful.

Solution

We apply the quantile function to compute the percentiles of eruptions with the desired percentage ratios.

Answer

The 32^nd, 57^th and 98^th percentiles of the eruption duration are 2.3952, 4.1330 and 4.9330 minutes respectively.

Exercise

Find the 17^th, 43^rd, 67^th and 85^th percentiles of the eruption waiting periods in faithful.

Note

There are several algorithms for the computation of percentiles. Details can be found in the R documentation via help(quantile).