Quadratic regression program for TI-81 - works in same
manner as built-in linear regression.
----begin documentation---
To use QUADREG store data points is STAT just as if doing
a linear regression.  Then execute QUADREG.  To check try the
points (0,14.8),(10.13.9),(20,13.4),(30,13.5),(40,15.5) and
(46,18.3).  Results should be the quadratic equation
y=15.10365-.2246085x+.00617102x^2.  Program was suggested by
Introduction To Probability and Statistics, Alder & Roessler,
4th Edition, page 198 in which matrices is used to solve.
Note - a cubic regression program follows a similar pattern.
----end documentation---
----begin ASCII---
\START81\
\NAME=QUADREG 
\FILE=ti81_3.PRG
Disp "FIND A,B,C IN"
Disp "F(X)=A+BX+CX\^2\"
Disp ""
3->ARow
3->ACol
3->BRow
1->BCol
LinReg
n->E
1->N
0->C
0->Q
0->P
Lbl L
({x}(N))^3+C->C
({x}(N))^4+Q->Q
({x}(N))\^2\{y}(N)+P->P
IS>(N,E)
Goto L
n->[A](1,1)
\Sigma-x\->[A](1,2)
\Sigma-x^2\->[A](1,3)
\Sigma-x\->[A](2,1)
\Sigma-x^2\->[A](2,2)
C->[A](2,3)
\Sigma-x^2\->[A](3,1)
C->[A](3,2)
Q->[A](3,3)
\Sigma-y\->[B](1,1)
\Sigma-xy\->[B](2,1)
P->[B](3,1)
[A]\^-1\[B]->[C]
Disp "A,B,C="
Disp [C]
\STOP81\
----end ASCII----
----begin UUE----
begin 644 ti81_3.prg
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M)EIP)EMP2"SLMRPL[!,<=.P3''7L$QQV[!$<=^R;[(X<7>P1'&;L$!Q;[!`<
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M:.R_9AY='>R]9.R.'(8?$1X1'>R)'(8?$1X2'>R*'(8?$1X3'>R)'(8?$AX1
M'>R*'(8?$AX2'>Q;'(8?$AX3'>R*'(8?$QX1'>Q;'(8?$QX2'>QI'(8?$QX3
M'>R,'(<?$1X1'>R+'(<?$AX1'>QH'(<?$QX1'>R&1X<<B.RW+%D>6AY;("SL
$MXCS6```
`
end
----end UUE---
eof (end of file)



--
Peter L. A. Oakes ae012@leo.nmc.edu
Muskegon Community College
221 S Quarterline Rd
Muskegon MI 49442 (616)-777-0295