SUBROUTINE EXVAL(OBS,E)
C
C          THIS SUBROUTINE COMPUTES THE Chi-square VALUE FOR
C          A 2 X 3 CONTINGENCY TABLE.
C          CONTINGENCY TABLE IS DESCRIBED IN SUBROUTINE "GOF2"
C
      IMPLICIT DOUBLE PRECISION (A-H,O-Z)
      DOUBLE PRECISION OBS(2,4),OBS1(2,4),E(2,4),ROW(2),COL(4)
      ROW(1)=OBS(1,1)+OBS(1,2)+OBS(1,3)+OBS(1,4)
      ROW(2)=OBS(2,1)+OBS(2,2)+OBS(2,3)+OBS(2,4)
      TOTL=ROW(1)+ROW(2)
      IF(TOTL.LE..0D0)GO TO 70
      DO 10 J=1,4
        OBS1(1,J)=OBS(1,J)
        OBS1(2,J)=OBS(2,J)
        COL(J)=OBS(1,J)+OBS(2,J)
        E(1,J)=ROW(1)*COL(J)/TOTL
   10   E(2,J)=ROW(2)*COL(J)/TOTL
   70 RETURN
      END