20060301
Drawing Quadratic, Cubic, and Quartic Regre
ss
ion Graph
s
You can draw a quadratic, cubic, or quartic regression graph based on the plotted points.
These graphs use the method of least squares to draw a curve that passes the vicinity of
as many data points as possible. These graphs can be expressed as quadratic, cubic, and
quartic regression expressions.
The following procedure shows how to graph a quadratic regression only. Graphing the cubic
and quartic regressions are similar.
S
Cla
ss
Pad Operation (Quadratic Regre
ss
ion)
Start the graphing operation from the Statistics application’s Graph window or List window.
From the Graph window
Tap [Calc] [Quadratic Reg] [OK] [OK]
.
• For cubic regression tap [Cubic Reg] and for quartic regression tap [Quartic Reg]
instead of [Quadratic Reg].
From the Li
s
t window
Tap [SetGraph][Setting...], or
'
.
On the Set StatGraphs dialog box that appears, configure a StatGraph setup with the
setting shown below, and then tap [Set].
Type: QuadR
• For cubic regression select [CubicR] and for quartic regression tap [QuartR] instead
of [QuadR].
Tap
x
to draw the graph.
7-5-7
Graphing Paired-Variable Statistical Data
The following are the model formulas for each type of regression.
Quadratic Regre
ss
ion
Model
Formula:
y
=
a
·
x
2
+
b
·
x
+
c
a
:
quadratic regression coefficient
b
:
linear regression coefficient
c
:
regression constant term (
y
-intercept)
r
2
:
coefficient of determination
MSe
: mean square error
• MSe
=
1
n
–
3
i
=1
n
(
y
i
– (
a·x
i
+
b·x
i
+
c
))
2
2
Summary of Contents for ClassPad 330
Page 11: ...20060301 20090601 ClassPad 330 ClassPad OS Version 3 04 ...
Page 277: ...20060301 3 3 10 Storing Functions 3 Tap AND Plot OR Plot ...
Page 779: ...20090601 S Graph Line Clustered C S Graph Line Stacked E 13 9 2 Graphing ...
Page 780: ...20090601 S Graph Line 100 Stacked F S Graph Column Clustered G 13 9 3 Graphing ...
Page 781: ...20090601 S Graph Column Stacked I S Graph Column 100 Stacked J 13 9 4 Graphing ...
Page 782: ...20090601 S Graph Bar Clustered K S Graph Bar Stacked 9 13 9 5 Graphing ...