Go to "Analysis sows" - "Group analysis". 


Here you can decide, which periods that occur on the group analysis by clicking "Edit".


In the "Weeks" column, you enter how many weeks to look back. Furthermore, you can view more/fewer "Deviation" columns by adding/removing the marks. You can also change the name of the group 

 


Close the window and calculate the analysis again to view the result of the new setup.