The QUARTILE() function returns the a specified quartile value of a range of data points. The syntax for the function is QUARTILE (array, quart). The argument "array" can be an array, a referenced range of cells or a named range. However referenced cells that do not contain values or that cannot be converted to numeric values such as text, logical values or empty cells will be ignored. Note: If the "array" is empty or values in the "quart" argument are not between 0 and 4, the function will return a #NUM error. The "array" argument holds the data points of the distribution. The "quart" argument has a value between 0 and 4, specifying the desired quartile. 0 Returns the smallest value in the data set (0th percentile value) 1 Gives the first quartile (25th percentile value) 2 Gives the second quartile (50th percentile or MEDIAN value) 3 Gives the third quartile (75th percentile value) 4 Gives the fourth quartile (100 percentile or MAX value) The QUARTILE function calculates a specific quartile value using the "array" data values and the selected quartile form "quart" returning the value to the cell. For example: QUARTILE({1,2,3,4,5,6,7,8,9,10},3) = 7.75 This means that the value of the 3rd quartile or 75th percentile is equal to 7.75 .This is between the actual values of the data points. However it represents the boundray between quartile ranges. This result defines all data points in the "array" that are over 7.75 to be in the 3rd quartile of the distribution. Putting the points 8 and 9 in the 75th percentil of values (10 is in the 4th quartile is not included).

How to use the QUARTILE() function: Type " =QUARTILE( " Enter the coordinates of the"array" cell "A2:A10" Type a comma. Enter the value for the "quart", "2". Type ")" then press the "Enter" key.

The function can also be used to find interquartile range (the difference between the first and third quartiles) which gives a reliable measure of the spread of the data distribution (ignoring extreme values). For example: QUARTILE(({1,2,3,4,5,6,7,8,9,10},3) - QUARTILE({1,2,3,4,5,6,7,8,9,10},1) = 4.5 That is the difference between the 75th and the 25th percentile is 4.5 which gives the size of the spread of the middle 50% percent of the data in the distribution. Note: The interquartile range also tells you the size of the box in a box plot chart.