Happy Formula Friday!.  This Friday we are a bit stuck in the middle, yes you guessed it – its MEDIAN time.

As you probably know, the MEAN is a useful way to summarise a group of numbers.  But if you use it a few times, you may notice that it really is sensitive to extreme values that maybe part of your data set so with the addition of one extreme number to your data then your MEAN not be a good representative of your data set.

Let’s look at an example.  Say you are looking at the number of stokes per minute members of a swim team achieve. 49, 50, 55, 55, and 56.

The group has five swimmers has a MEAN  or AVERAGE  number of stokes per minute of 53. Say the group changes slightly and one swimmer of 55 strokes per minute leaves and a new one joins the group who swims at a whopping 99 strokes per minute.

If we calculate the new MEAN or AVERAGE (which happens to now be 62) it really is not a good representation of our group of swimmers’ speeds as except for the new super swimmer who joined the group, no other member swims nearly that fast.

 

Here is where our MEDIAN comes in very handy.   The MEDIAN is the middle value in a group of numbers.  Just arrange the numbers in order and the median is the value below which half of the scores fall and above which half the scores fall.

So, using our example our original MEDIAN would at 55…….. Along with the AVERAGE of 53 strokes per minute.

 

Add in the new super swimmer, yes you guessed it the MEDIAN stays the same but as we have already seen the AVERAGE jumps to 62.

 

 

In this case it is way more representative of the stroke rate of our swim group.

Here are the steps to use the MEDIAN function in Excel

1. Type your data into your worksheet
2. Select a cell to display your result
3. From the Statistical Functions Menu select MEDIAN to open the dialog box
4. Select Your Data Set
5. Hit Ok