mean function in the Factory

The mean function displays the average attribute value calculated mathematically. It is the sum of the values divided by the number of values. (E.g.: the mean between 2; 3; 10 is 5).

This function doesn’t work with nominal attributes. For nominal attributes you can use the mode function.

The mean is available also by:

Function and parameters

mean(column, group)




It identifies the column to which you want to apply the formula. The column parameter is mandatory.


It allows you to group the results by a certain column.


The following example uses the Students Performance dataset.



  • In the example here, we want to retrieve the mean of the math score attribute.

  • We write the following formula:

  • mean($"math score")

So, the mean of the math score attribute is 66.089.

  • We also want to group our results by the test preparation course attribute, so the formula will become:

  • mean($"math score",$"test preparation course")

  • The results are as follows:

    • The mean of the math score of those who have done no test preparation course (none) is 64.078.

    • The mean of the math score of those who have completed the test preparation course is 69.696.