Where y is the percentile we want to find and n is the number of observations in a dataset. The median is the middle value of the data set. There are three quartiles.
Interquartile Range Q3 Q1.
The first and third quartiles are also called the lower and upper quartiles respectively. Where ℓ 10 lower boundary of the relevant Quartile class C 5 value of cf. Put the list of numbers in order. The upper half of a data set is the set of all values that are to the right of the median value when the data has been put into increasing order.