Quartiles Calculation

by Geethalakshmi[ Edit ] 2011-10-25 10:30:56

Quartiles Calculation

What are the quartiles?

The first quartile, or 25th percentile xL (also written as Q1), is the number for which 25% of values in the data set are smaller than xL.

The second quartile or 50th percentile, xm (also written as Q2) is also known as the median. It represents the value for which 50% of observations are lower and 50% are higher.

The third quartile or 75th percentile, xH (Q3) is the value such that 75% of the observations are less than xH

How are quartiles calculated

This calculator uses the following system to find the quartiles:

n is the number of observations. x1, x2 ... xn are the values sorted from the lowest to the highest.

By 'integer' we mean the integer portion and by decimal, the decimal portion (the part of the number following the decimal point) of a number.

First quartile formulas

If