Formula Help Needed

I need a status formula for the parent row of up to 5 children rows. 

The children rows have a control rating of 1-3

If rows 1-5 have a control rating of 1, the status column should reflect "Closed" in the parent row.

If rows 1-5 is 2 or 3 then parent row should show "Work In Progress"

If ALL are blank then status should be "Not Started"

My issue is, when 3 of the children rows are populated differently:

example: 

row 14 - "Control Rating" = 3

row 15 - "Control Rating" = 2

row 16 - "Control Rating" = 1 

In this case, the Status Column should reflect "Closed". How can I state in the formula that "1" is priority over 2-3 and 2-3 is priority over blank?