IF X is Greater or Smaller than give an outcome

need help with the following formula for excel. Is not working, the only feedback i'm getting is #VALUE! outcome. What I'm trying to do is simply:

• F5≥-8 = Big,
• -3≤F5≤-7.99999= Bigger,

• F5≥-2.9999999 = "Blank" <--- No outcome display required

  =IF((F5)>=-8, "Big"),IF((F5)>=-3, "Bigger"), IF((F5)<=-1,"Biggest")