VERSION 5.00
Begin VB.Form Form1 
   Caption         =   "Form1"
   ClientHeight    =   3990
   ClientLeft      =   60
   ClientTop       =   345
   ClientWidth     =   4680
   LinkTopic       =   "Form1"
   ScaleHeight     =   3990
   ScaleWidth      =   4680
   StartUpPosition =   3  'Windows Default
   Begin VB.CommandButton Command1 
      Caption         =   "Command1"
      Height          =   375
      Left            =   2880
      TabIndex        =   0
      Top             =   3240
      Width           =   1335
   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 D11R9
    'Driver for routine CHSTWO
    NPTS = 2000
    NBINS = 10
    Dim BINS1(10), BINS2(10)
    IDUM = -17
    For J = 1 To NBINS
        BINS1(J) = 0#
        BINS2(J) = 0#
    Next J
    For I = 1 To NPTS
        X = EXPDEV(IDUM)
        IBIN = Int(X * NBINS / 3#) + 1
        If IBIN <= NBINS Then BINS1(IBIN) = BINS1(IBIN) + 1#
        X = EXPDEV(IDUM)
        IBIN = Int(X * NBINS / 3#) + 1
        If IBIN <= NBINS Then BINS2(IBIN) = BINS2(IBIN) + 1#
    Next I
    Call CHSTWO(BINS1(), BINS2(), NBINS, -1, DF, CHSQ, PROB)
    Print
    Print Tab(5); "Dataset 1     Dataset 2"
    For I = 1 To NBINS
        Print Tab(5); Format$(BINS1(I), "###.#0");
        Print Tab(19); Format$(BINS2(I), "###.#0")
    Next I
    Print
    Print Tab(5); "Chi-squared:  ", Format(CHSQ, ".###0E+00")
    Print Tab(5); "Probability: ", Format(PROB, ".###0E+00")
End Sub
Sub CHSTWO(BINS1(), BINS2(), NBINS, KNSTRN, DF, CHSQ, PROB)
    DF = NBINS - 1 - KNSTRN
    CHSQ = 0#
    For J = 1 To NBINS
        If BINS1(J) = 0# And BINS2(J) = 0# Then
          DF = DF - 1#
        Else
          CHSQ = CHSQ + (BINS1(J) - BINS2(J)) ^ 2 / (BINS1(J) + BINS2(J))
        End If
    Next J
    PROB = GAMMQ(0.5 * DF, 0.5 * CHSQ)
End Sub
  Function GAMMQ(A, X)
      If X < 0# Or A <= 0# Then
         Print "PAUSE"
         Exit Function
      End If
      If X < A + 1# Then
          Call GSER(GAMSER, A, X, GLN)
          GAMMQ = 1# - GAMSER
      Else
          Call GCF(GAMMCF, A, X, GLN)
          GAMMQ = GAMMCF
      End If
   End Function
   Sub GCF(GAMMCF, A, X, GLN)
      ITMAX = 100
      EPS = 0.0000003
      GLN = GAMMLN(A)
      GOLD = 0#
      A0 = 1#
      A1 = X
      B0 = 0#
      B1 = 1#
      FAC = 1#
      For N = 1 To ITMAX
          AN = N

          ANA = AN - A
          A0 = (A1 + A0 * ANA) * FAC
          B0 = (B1 + B0 * ANA) * FAC
          ANF = AN * FAC
          A1 = X * A0 + ANF * A1
          B1 = X * B0 + ANF * B1
          If A1 <> 0# Then
              FAC = 1# / A1
              G = B1 * FAC
              If Abs((G - GOLD) / G) < EPS Then GoTo 1
              GOLD = G
          End If
      Next N
      Print "A too large, ITMAX too small"
1     GAMMCF = Exp(-X + A * Log(X) - GLN) * G
   End Sub
   Sub GSER(GAMSER, A, X, GLN)
      ITMAX = 100
      EPS = 0.0000003
      GLN = GAMMLN(A)
      If X <= 0# Then
          If X < 0# Then
             Print " PAUSE"
             Exit Sub
          End If
          GAMSER = 0#
          Exit Sub
      End If
      AP = A
      Sum = 1# / A
      DEL = Sum
      For N = 1 To ITMAX
          AP = AP + 1#
          DEL = DEL * X / AP
          Sum = Sum + DEL
          If Abs(DEL) < Abs(Sum) * EPS Then GoTo 1
      Next N
      Print "A too large, ITMAX too small"
1     GAMSER = Sum * Exp(-X + A * Log(X) - GLN)
   End Sub
   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 EXPDEV(IDUM)
      Randomize
      EXPDEV = -Log(Rnd)
End Function