VB编写的蒙特卡罗方法产生正态分布随机数

上次给出了C语言编写的正态分布随机数程序，这次是VB的，转载请注明出处

Private Sub Command1_Click()
Dim i, n As Integer
Dim mu, sigma As Double
mu = Text1.Text
sigma = Text2.Text
n = Text3.Text
Open "data.txt" For Output As #1
For i = 0 To n
If i = n Then Exit For
Text4.Text = Text4.Text & Str(sta(mu, sigma)) & Chr(9)
Write #1, sta(mu, sigma)
Next
Close #1
End Sub

 Function sta(mu, sigma As Double) As Double
    Dim r1, r2 As Double
    Dim pi As Double
    pi = 3.1415926
    r1 = Rnd
    r2 = Rnd
    sta = Int(Sqr(-2 * Log(r1)) * Cos(2 * pi * r2) * sigma + mu)
End Function