Chapter 12: Statistics
201
LinReg (ax+b)
LinReg(ax+b)
(linear regression) fits the model equation y=ax+b to the data using a least-squares fit.
It displays values for
a
(slope) and
b
(y-intercept); when
DiagnosticOn
is set, it also displays values
for
r
2
and
r
.
LinReg(ax+b)
[
Xlistname
,
Ylistname
,
freqlist
,
regequ
]
QuadReg (ax
2
+bx+c)
QuadReg
(quadratic regression) fits the second-degree polynomial y=ax
2
+bx+c to the data. It
displays values for
a
,
b
, and
c
; when
DiagnosticOn
is set, it also displays a value for
R
2
. For three
data points, the equation is a polynomial fit; for four or more, it is a polynomial regression. At least
three data points are required.
QuadReg
[
Xlistname
,
Ylistname
,
freqlist
,
regequ
]
CubicReg—(ax
3
+bx
2
+cx+d)
CubicReg
(cubic regression) fits the third-degree polynomial y=ax
3
+bx
2
+cx+d to the data. It
displays values for
a
,
b
,
c
, and
d
; when
DiagnosticOn
is set, it also displays a value for
R
2
. For four
points, the equation is a polynomial fit; for five or more, it is a polynomial regression. At least four
points are required.
CubicReg
[
Xlistname
,
Ylistname
,
freqlist
,
regequ
]
