vb实现类似excel的Trimmean函数

如果用vb实现如excel的Trimmean函数

语法形式为TRIMMEAN(Array,Percent)
rray为需要进行筛选并求平均值的数组或数据区域，Percent为计算时所要除去的数据点的比例。
而且数组里有0不列入平均值计算 VBA的函数可以直接使用 Private Function GetAverage(Source() As Single, n As Integer) As Single '去除最大最小n个数求平均值
    InsertSort Source
    Dim i As Integer, Sum As Single
    Dim k As Integer
    '--0的个数-----
    Dim n0 As Integer '为0
    Dim nn0 As Integer '不为0
    n0 = 0
    nn0 = 0
    For i = LBound(Source) To UBound(Source)
        If Source(i) = 0 Then
            n0 = n0 + 1
        End If
    Next
    '-----------
    For k = n0 + n To UBound(Source) - n
        Sum = Sum + Source(k)
        nn0 = nn0 + 1
    Next
    If nn0 > 0 Then
         GetAverage = Sum / nn0
    Else
        GetAverage = -1
     End If
End Function
Private Sub InsertSort(Source() As Single) '由小到大排序
    Dim i As Long, j As Long, k As Long, c As Long
    Dim tmpArr() As Single
    ReDim n(LBound(Source) To UBound(Source)) As Single
    c = LBound(Source)
    For i = LBound(Source) To UBound(Source)
        For j = LBound(Source) To c - 1
            If Source(i) <= n(j) Then Exit For
        Next
        For k = c - 1 To j Step -1
            n(k + 1) = n(k)
        Next
        n(j) = Source(i)
        c = c + 1
    Next
    For i = LBound(Source) To UBound(Source)
        Source(i) = n(i)
    Next
End Sub

Private Sub Command1_Click()

Dim c(10) As Singlec(0) = 2
c(1) = 8
c(2) = 2
c(3) = 3
c(4) = 4
c(5) = 0
c(6) = 0
c(7) = 2
c(8) = 0
c(9) = 0
c(10) = 0
Text1.Text = GetAverage(c, 1)
End Sub

写了一个，得出2.75

这种函数很简单啊。。。。。。。。那有没有更合理的算法

补充：VB ,  基础类