VERSION 5.00
Begin VB.Form Form1 
   Caption         =   "Form1"
   ClientHeight    =   3840
   ClientLeft      =   60
   ClientTop       =   345
   ClientWidth     =   4680
   LinkTopic       =   "Form1"
   ScaleHeight     =   3840
   ScaleWidth      =   4680
   StartUpPosition =   3  'Windows Default
   Begin VB.CommandButton Command1 
      Caption         =   "Command1"
      Height          =   375
      Left            =   3120
      TabIndex        =   0
      Top             =   3240
      Width           =   1215
   End
End
Attribute VB_Name = "Form1"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = False
Private Sub Command1_Click()
    'PROGRAM D11R6A
    'Driver for routine TUTEST
    NPTS = 5000
    MPTS = 1000
    EPS = 0.02
    NSHFT = 10
    VAR1 = 1#
    VAR2 = 4#
    Dim DATA1(5000), DATA2(1000)
    'Generate two Gaussian distributions of different variance
    IDUM = -51773
    FCTR1 = Sqr(VAR1)
    For I = 1 To NPTS
        DATA1(I) = FCTR1 * GASDEV(IDUM)
    Next I
    FCTR2 = Sqr(VAR2)
    For I = 1 To MPTS
        DATA2(I) = (NSHFT / 2#) * EPS + FCTR2 * GASDEV(IDUM)
    Next I
    Print
    Print Tab(5); "Distribution #1 : variance =  "; Format$(VAR1, "#.00")
    Print Tab(5); "Distribution #2 : variance =  "; Format$(VAR2, "#.00")
    Print
    Print Tab(5); "Shift       T     Probability"
    For I = 1 To NSHFT + 1
        Call TUTEST(DATA1, NPTS, DATA2, MPTS, T, PROB)
        SHIFT = (I - 1) * EPS
        Print Tab(5); Format$(SHIFT, "#.#0");
        Print Tab(15); Format$(T, "#.#0");
        Print Tab(25); Format$(PROB, "#.#0")
        For J = 1 To NPTS
            DATA1(J) = DATA1(J) + EPS
      Next J
    Next I
End Sub
Sub TUTEST(DATA1(), N1, DATA2(), N2, T, PROB)
    Call AVEVAR(DATA1(), N1, AVE1, VAR1)
    Call AVEVAR(DATA2(), N2, AVE2, VAR2)
    T = (AVE1 - AVE2) / Sqr(VAR1 / N1 + VAR2 / N2)
    AAA = (VAR1 / N1 + VAR2 / N2) ^ 2
    DF = AAA / ((VAR1 / N1) ^ 2 / (N1 - 1) + (VAR2 / N2) ^ 2 / (N2 - 1))
    PROB = BETAI(0.5 * DF, 0.5, DF / (DF + T ^ 2))
End Sub
Sub AVEVAR(DATA(), N, AVE, VAR)
      AVE = 0#
      VAR = 0#
      For J = 1 To N
          AVE = AVE + DATA(J)
      Next J
      AVE = AVE / N
      For J = 1 To N
          S = DATA(J) - AVE
          VAR = VAR + S * S
      Next J
      VAR = VAR / (N - 1)
End Sub
   Function GASDEV(IDUM)
      Static ISET, GSET
      If ISET = 0 Then
        Do
          Randomize
          V1 = 2# * Rnd - 1#
          V2 = 2# * Rnd - 1#
          R = V1 ^ 2 + V2 ^ 2
        Loop While R >= 1# Or R = 0
        FAC = Sqr(-2# * Log(R) / R)
        GSET = V1 * FAC
        GASDEV = V2 * FAC
        ISET = 1
      Else
        GASDEV = GSET
        ISET = 0
      End If
   End Function
   Function BETAI(A, B, X)
      If X < 0# Or X > 1# Then Print "bad argument X in BETAI"
      If X = 0# Or X = 1# Then
          BT = 0#
      Else
          AAA = GAMMLN(A + B) - GAMMLN(A) - GAMMLN(B)
          BT = Exp(AAA + A * Log(X) + B * Log(1# - X))
      End If
      If X < (A + 1#) / (A + B + 2#) Then
          BETAI = BT * BETACF(A, B, X) / A
          Exit Function
      Else
          BETAI = 1# - BT * BETACF(B, A, 1# - X) / B
          Exit Function
      End If
   End Function
   Function GAMMLN(XX)
      Dim COF(6)
      COF(1) = 76.18009173
      COF(2) = -86.50532033
      COF(3) = 24.01409822
      COF(4) = -1.231739516
      COF(5) = 0.00120858003
      COF(6) = -0.00000536382
      STP = 2.50662827465
      HALF = 0.5
      ONE = 1#
      FPF = 5.5
      X = XX - ONE
      TMP = X + FPF
      TMP = (X + HALF) * Log(TMP) - TMP
      SER = ONE
      For J = 1 To 6
          X = X + ONE
          SER = SER + COF(J) / X
    Next J
      GAMMLN = TMP + Log(STP * SER)
   End Function
   Function BETACF(A, B, X)
      ITMAX = 100
      EPS = 0.0000003
      AM = 1#
      BM = 1#
      AZ = 1#
      QAB = A + B
      QAP = A + 1#
      QAM = A - 1#
      BZ = 1# - QAB * X / QAP
      For M = 1 To ITMAX
          EM = M
          TEM = EM + EM
          D = EM * (B - M) * X / ((QAM + TEM) * (A + TEM))
          AP = AZ + D * AM
          BP = BZ + D * BM
          D = -(A + EM) * (QAB + EM) * X / ((A + TEM) * (QAP + TEM))
          AAP = AP + D * AZ
          BPP = BP + D * BZ
          AOLD = AZ
          AM = AP / BPP
          BM = BP / BPP
          AZ = AAP / BPP
          BZ = 1#
          If Abs(AZ - AOLD) < EPS * Abs(AZ) Then GoTo 1
      Next M
      Print "A or B too big, or ITMAX too small"
1     BETACF = AZ
   End Function