The QUARTILE 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.