Excel looking group interval or frequency (formula an VBA Macro)

Excel Formula to looking group of interval data
=IF(AND(IF(ISNUMBER(A1)=FALSE,0,A1)<=80,A2>80),-1,0)
Total minutes	Status dengan formula			Group
85	-1		==>	Group 1
30	0
89	-1		==>	Group 2
89	0
80	0
30	0
89	-1		==>	Group 3
89	0
30	0
60	0
89	-1		==>	Group 4
99	0
89	0
86	0
80	0
60	0
89	-1		==>	Group 5
81	0
60	0
89	-1		==>	Group 6
81	0
There are six (6) group of data interval which has value > 80

I'm creating vba function as well to looking the Group Frequency in Excel


Function cariinterval(sel1 As String, sel2 As Single) As Single


Dim vsel1 As Single

If IsNumeric(sel1) = False Then
    vsel1 = 0
    Else
    vsel1 = sel1
End If

If vsel1 <= 80 And sel2 > 80 Then
    cariinterval = -1
    Else
    cariinterval = 0
    End If




End Function