SUBROUTINE REGRS(PRS,VOL,FLO,ACC,MOBS)
	COMMON IBUFF(255),DUM(85),MANU,IBLK,CP,CV,CF
	COMMON/BLK1/VOLN(250),VOLX(250),FLON(260),FLOX(260),PRSN(250)
	COMMON/BLK2/ACCN(250),ACCX(250),PRSX(250)
	COMMON/BLK3/INEG,IPOS,IDIM,ITMP,IDIM1,IPAS,ISTOP,IREC
	COMMON/BLK4/HOLD(30),K,X,Y,APOS,J
	COMMON/BLK5/AMAT(5,5),COEF(4),COV(5,5),COR(5,5),A21(4)
	COMMON/BLK6/SD(5),A12(4),CEPT,DET,EPS,SX(5),SXY(5),SY
	DIMENSION PRS(1),VOL(1),FLO(1),ACC(1)
	EPS=1.0E-20
	SY=0.
	SYY=0.
	DO 10 I=1,4
	SX(I)=0.
  10	SXY(I)=0.
	DO 15 I=1,MOBS
	VOL(I)=VOL(I)*CV
	PRS(I)=PRS(I)*CP
	FLO(I)=FLO(I)*CF
  15	ACC(I)=ACC(I)*CF
	DO 30 I=1,5
	DO 20 JJ=1,5
  20	AMAT(I,JJ)=0.
  30	CONTINUE
C	.....COMPUTE SUMS AND PRODUCTS.....
	DO 40 I=1,MOBS
	SYY=SYY+PRS(I)*PRS(I)
	SY=SY+PRS(I)
	SX(1)=SX(1)+VOL(I)
	SX(2)=SX(2)+FLO(I)
	SX(3)=SX(3)+FLO(I)**2
	SX(4)=SX(4)+ACC(I)
	SXY(1)=SXY(1)+VOL(I)*PRS(I)
	SXY(2)=SXY(2)+FLO(I)*PRS(I)
	SXY(3)=SXY(3)+FLO(I)**2*PRS(I)
  40	SXY(4)=SXY(4)+ACC(I)*PRS(I)
C	.....COMPUTE COEFFICIENTS OF AMAT(I,JJ).....
	AM=FLOAT(MOBS)
	DO 50 I=1,4
  	AMAT(I,5)=SXY(I)-(SX(I)*SY)/AM
  50	AMAT(5,I)=AMAT(I,5)
	DO 60 I=1,MOBS
	AMAT(1,1)=AMAT(1,1)+VOL(I)*VOL(I)
	AMAT(1,2)=AMAT(1,2)+VOL(I)*FLO(I)
	AMAT(1,3)=AMAT(1,3)+VOL(I)*FLO(I)**2
	AMAT(1,4)=AMAT(1,4)+VOL(I)*ACC(I)
	AMAT(2,2)=AMAT(2,2)+FLO(I)*FLO(I)
	AMAT(2,3)=AMAT(2,3)+FLO(I)*FLO(I)**2
	AMAT(2,4)=AMAT(2,4)+FLO(I)*ACC(I)
	AMAT(3,3)=AMAT(3,3)+FLO(I)**2*FLO(I)**2
	AMAT(3,4)=AMAT(3,4)+FLO(I)**2*ACC(I)
  60	AMAT(4,4)=AMAT(4,4)+ACC(I)*ACC(I)
	L=0
	DO 80 I=1,4
	L=L+1
	DO 70 JJ=L,4
	AMAT(JJ,I)=AMAT(I,JJ)-(SX(I)*SX(JJ))/AM
  70	AMAT(I,JJ)=AMAT(JJ,I)
	A12(I)=AMAT(I,5)
	A21(I)=AMAT(5,I)
  80	CONTINUE
	AMAT(5,5)=SYY-(SY**2)/AM
	APOS=AMAT(5,5)
	Z=AM-1.
	DO 85 I=1,5
	DO 83 L=1,5
  83	COV(I,L)=AMAT(I,L)/Z
  85	SD(I)=SQRT(COV(I,I))
	DO 88 I=1,5
	DO 86 L=1,5
  86	COR(I,L)=COV(I,L)/(SD(I)*SD(L))
  88	CONTINUE
	X=AM
	RETURN
	END