Category : Recently Uploaded Files
Archive   : PAPCW10.ZIP
Filename : REGRESS.PRG

; simple linear regression y = a + bx
; b = (n*sum(xy) - sum(y)*sum(x))/(n*sum(sqr(x)) - sqr((sum(x)))
; a = mean(y)-b*mean(x)
; R1 sum(x)
; R2 sum(y)
; R3 sum(sqr(x))
; R4 sum(sqr(y))
; R5 sum(x*y)
; R6 n

LBL regress
; clear registers 1-6
1.00601 0 sto
LBL clear
0 rcl 0 swap sto
0 isg
GTO clear

LBL dataentry
PROMPT "Enter x and y: "
GTO calc ; only if a null line is entered
1 6 STO+
DUP 2 STO+
DUP SQR 4 STO+
SWAP
DUP 1 STO+
DUP SQR 3 STO+
* 5 STO+
GTO dataentry

LBL calc ;
; calculate b = (n*sum(xy) - sum(y)*sum(x))/(n*sum(sqr(x)) - sqr((sum(x)))
6 RCL 5 RCL * 2 RCL 1 RCL * - 6 RCL 3 RCL * 1 RCL SQR - /
; calculate a = mean(y)-b*mean(x)
2 RCL 6 RCL / OVER 1 RCL 6 RCL / * -
PUTS "a = " 0 WIDTH PUTSTACK PUTS "\n"
8 STO
PUTS "b = " 0 WIDTH PUTSTACK PUTS "\n"
9 STO
; calculate RSQ = (a*sum(y) + b*sum(xy) - mean(sqr(sum(y))))/ (sum(sqr(y)) - mean(sqr(sum(y)))
8 RCL 2 RCL * 9 RCL 5 RCL * + 2 RCL SQR 6 RCL / DUP 0 STO - 4 RCL 0 RCL - /
4 FIX PUTS "RSQ = " 0 WIDTH PUTSTACK PUTS "\n"
CLST
END