Achso hatte mich da vertan. Jetzt passt es für Excel 2007 (Dateiendungen) etc, und mein Pfad ist raus. Falls es andere als .xlsx Datein sind, dass in Zeile 35 und 39 anpassen. 

Gruß

Option Explicit

Sub berechnen()
Dim name As String
Dim name2 As String
Dim mitwe
Dim max
Dim min
Dim i As Long
Dim bedingungen
Dim pfad As String
Dim suche As String
Dim zeile As Long
Dim summe
Dim formel1
Dim formel2
Dim anzahl As Long

bedingungen = Array("", "NEG_HT", "NEG_NT", "POS_HT", "POS_NT")

pfad = "       "  'hier den Pfad eingeben
If Right(pfad, 1) = "\" Then pfad = Left(pfad, Len(pfad) - 1)

Application.ScreenUpdating = False
name = ThisWorkbook.name

Workbooks(name).Worksheets(1).Cells(1, 1) = "Dateiname"
For i = 1 To 4
    Workbooks(name).Worksheets(1).Cells(1, 2 + (i - 1) * 3) = "Max " & bedingungen(i)
    Workbooks(name).Worksheets(1).Cells(1, 3 + (i - 1) * 3) = "Min " & bedingungen(i)
    Workbooks(name).Worksheets(1).Cells(1, 4 + (i - 1) * 3) = "Mittwelwert " & bedingungen(i)
Next i

zeile = 2
suche = Dir(pfad & "\*.xlsx")   'suche nimmt den Dateinamen auf
  
Do Until suche = ""

        If Left(suche, 6) = "Anonym" And Right(suche, 9) = "2015.xlsx" Then  'könnte man noch ausbauen
         
            Workbooks.Open pfad & "\" & suche
            name2 = ActiveWorkbook.name
            For i = 1 To 4
                anzahl = Application.WorksheetFunction.CountIf(Workbooks(name2).Worksheets(1).Columns(2), bedingungen(i))
                summe = Application.WorksheetFunction.SumIf(Worksheets(1).Columns(2), bedingungen(i), Worksheets(1).Columns(3))
                mitwe = summe / anzahl
            'Spalte B Bedingungen, Spalte C Werte
                formel1 = "=MAX((B1:B5100=" & Chr(34) & bedingungen(i) & Chr(34) & ")*(C1:C5100))"
                formel2 = "=SVERWEIS(" & Chr(34) & bedingungen(i) & Chr(34) & ";B1:C5100;2;FALSCH)"
                Workbooks(name2).Worksheets(1).Cells(1, 4).FormulaArray = formel1
                max = Worksheets(1).Cells(1, 4).Value
                Workbooks(name2).Worksheets(1).Columns("B:C").Sort Key1:=Workbooks(name2).Worksheets(1).Range("B1"), Order1:=xlAscending, Header:=xlGuess, OrderCustom:=1, MatchCase:=False, Orientation:=xlTopToBottom, DataOption1:=xlSortNormal
                Workbooks(name2).Worksheets(1).Cells(1, 5).FormulaLocal = formel2
                min = Worksheets(1).Cells(1, 5).Value
                       
                Workbooks(name).Worksheets(1).Cells(zeile, 4 + (i - 1) * 3) = mitwe
                Workbooks(name).Worksheets(1).Cells(zeile, 3 + (i - 1) * 3) = min
                Workbooks(name).Worksheets(1).Cells(zeile, 2 + (i - 1) * 3) = max
            Next i
           
            Workbooks(name2).Close savechanges:=False
           
            Workbooks(name).Worksheets(1).Cells(zeile, 1) = suche
            zeile = zeile + 1
        End If
  
          
    suche = Dir()
Loop
Workbooks(name).Worksheets(1).Range("A:M").Columns.AutoFit
Workbooks(name).Worksheets(1).Range("A:M").HorizontalAlignment = xlCenter
Application.ScreenUpdating = True

End Sub