## Friday, 8 May 2020

### Using quartiles in Excel

When I am analysing semester results from my classes, I have some standard measures that I use. Those standard measures are: an average mark for each assessment; a lower quartile, which shows the minimum value for assessment; a 50th percentile, which shows the median value; and an upper quartile, which shows the maximum value.

When we are working in Excel these are exceptionally easy to set up. The formula for the quartiles is:
=QUARTILE(array, quartile value)
The quartile function includes an array, which is the range of the cells that you want the quartile to return a value for; and which particular quartile you want to measure (ie, minimum value, first quartile, median, third, or maximum).

Each one of these has a number which goes into the formula.
0 = Minimum value
1 = First quartile (25th percentile)
2 = Median value (50th percentile)
3 = Third quartile (75th percentile)
4 = Maximum value

So my median quartile might look like this:
=QUARTILE(A3:A75,2)
It is very easy when you know how!

Sam