1'        USE SYSTEM 'XBA'
2'   MONTHLY DATA MUST BE SAVED UNDER YOUR USER NUMBER IN A 
3'   DATA FILE.   
10 FILES FINPUT
20 PRINT "THIS PROGRAM USES MONTHLY DATA ONLY. DATA MUST BE ON DSK-FILE FINPUT.BAS";
50 PRINT
100 DIM A(20,12),B(20,12),D(20,12),E(12),F(12)
140 FOR M=1 TO 12
150 READ #1,A(N+1,M)
160 IF END #1 THEN 280
170 NEXT M
180 LET N=N+1
190 GOTO 140
280 LET S1 = 0
290 LET S2 = 0
300 LET S3 = 0
310 LET S4 = 0
320 LET S5 = 0
330 LET S6 = 0
340 FOR I = 1 TO N
350    FOR M= 1 TO 12
370       LET S1 = S1 + A(I,M)
380       LET S2 = S2 + (A(I,M)*A(I,M))
390       LET S3 = S3 + (A(I,M))*(((I-1)*12)+M)
400       LET S4 = S4 + (((I-1)*12)+M)*(((I-1)*12)+M)
410       LET S5 = S5 + 1
420       LET S6 = S6 + (((I-1)*12)+M)
430    NEXT M
440 NEXT I
450 LET B1= ((S5*S3)-(S1*S6))/((S5*S4)-(S6*S6))
460 LET A1= (S1-(B1*S6))/S5
470 PRINT "THE CALCULATED LINEAR TREND EQUATION IS:  ";
480 PRINT "Y ="A1"+"B1"* X"
490 PRINT
500 LET B2 = A1
510 FOR I = 1 TO N
520   FOR M = 1 TO 12
530      LET B2 = B2 + B1
540      LET B(I,M) = A(I,M)/B2
550   NEXT M
560 NEXT I
640 LET V = 0
650 FOR M = 1 TO 12
660    LET E(M) = 0
670    FOR I = 1 TO N
680      LET E(M) = E(M) + B(I,M)
690    NEXT I
700    LET E(M) = E(M)/N
710    LET V = V + E(M)
720 NEXT M
730 LET V = 12/V
740 FOR M = 1 TO 12
750   LET E(M) = E(M)*V
760 NEXT M
800 PRINT "HOW MANY YEARS WOULD YOU LIKE TO FORECAST";
810 INPUT N1
820 PRINT
830 PRINT
840 PRINT "YEAR","MONTH","FORECAST","SEASONAL FACTOR"
850 FOR I = N TO N+N1-1
860   PRINT
865   LET V1 = V2 = 0
870   FOR M = 1 TO 12
880      LET F(M) = (A1 + B1*((I*12)+M))*E(M)
890      PRINT I+1,M,F(M),E(M)
900      LET V1 = V1 + F(M)
910      LET V2 = V2 + E(M)
920   NEXT M
925   PRINT
930   PRINT "TOTAL"," ",V1,V2
940   PRINT
950 NEXT I
999 END