A to Z of Excel Functions: The QUARTILE.INC Function

Welcome back to our regular A to Z of Excel Functions blog.  Today we look at the QUARTILE.INC function.

The QUARTILE.INC function

Quartiles are three values that split sorted data into four parts, each with an equal number of observations.  Quartiles are a type of quantile (points in a distribution that relate to the rank order of values in that distribution.  They are denoted as follows:

• first quartile: also known as Q1 or the lower quartile
• second quartile: also known as Q2 or the median
• third quartile: also known as Q3 or the upper quartile.

There is one fewer quantile than the number of groups created.

QUARTILE.INC returns the quartile of the dataset, based upon percentile values from 0..1 inclusive.  Quartiles often are used in sales and survey data to divide populations into groups.  For example, you could use QUARTILE.INC to find the top 25% of incomes in a population.

QUARTILE.INC employs the following syntax to operate:

The QUARTILE.INC function has the following arguments:

• array: this is required and represents the array or cell range of numerical values for which you want the quartile value 
• quart: this is also required and denotes which value you wish to return.

It should be noted that:

•  if the array is empty, QUARTILE.INC returns the #NUM! error value
• if quart is not an integer, it is truncated
• if quart ≤ 0 or if quart ≥ 4, QUARTILE.INC returns the #NUM! error value
• MIN, MEDIAN and MAX theoretically return the same value as QUARTILE.INC when quart is equal to zero [0], two [2] and four [4] respectively. 

Please see my example below:

We’ll continue our A to Z of Excel Functions soon.  Keep checking back – there’s a new blog post every other business day.