谁帮我注释下这些代码？

GAOZHONG

请帮我注释如下这些代码：
Function Stdev(ParamArray Expr() As Variant) As String
    Dim curSun As Double, curAverageBad As Double, curBadSquare As Double
    Dim curAccuracy As Double
    Dim ExprLen As Long
    ExprLen = UBound(Expr) + 1
    curAccuracy = Val("10000000000000000")
    For i = 0 To ExprLen - 1
        curSun = curSun + Val(Expr(i))
    Next
    curAverageBad = Fix(curSun / ExprLen)
    For i = 0 To ExprLen - 1
        curBadSquare = curBadSquare + (Val(Expr(i)) - curAverageBad) ^ 2
    Next
    If ExprLen <= 20 Then
        Stdev = Fix(100 * Sqr(curBadSquare / (ExprLen - 1)) * curAccuracy + 0.5) / curAccuracy / 100
    Else
        Stdev = Fix(100 * Sqr(curBadSquare / ExprLen) * curAccuracy + 0.5) / curAccuracy / 100
    End If
End Function
多谢了！