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The data in the above can
SHIFT
be used to obtain the terms
of the regression formula
SHIFT
and
the
correlation
coefficient. Based on the
SHIFT
regression formula, the
18
SHIFT
estimated length of the
steel bar at 18°C an the
temperature when the bar
1000
is 1000mm long can be
SHIFT
calculated. The critical
coefficient
(r
2
)
and
covariance
(
ALPHA
x
)
1
)
*** Erroneous data clearing / correction (correct data operation: 10
1)
If 11
,
SHIFT
2)
If 11
,
SHIFT
3)
If 11
,
SHIFT
1003
,
CL
2.5.4 Logarithmic regression
The regression formula is y=A+B.lnx. Enter the x data as the logarithm (ln) of x, and the y data inputs
G
the same as that for linear regression.
Estimated values x, and y based on the regression formula can be calculated using the following
G
formulas:
^
y = A +B lnx
The same operation as with linear regression can be used to obtain the regression coefficient and for
G
making corrections. To obtain the estimated value y,
obtain estimated value x, y
Furthermore, Σx, Σx
Example
xi
yi
MODE
29
1.6
SHIFT
50
23.5
74
38.0
In
103
46.4
In
118
48.9
In
In
In
The data in the above can be
used to obtain the terms of
SHIFT
the regression formula and
the correlation coefficient.
SHIFT
Based on the regression
^
formula, estimated value y
SHIFT
can be obtained for xi=80,
^
and estimated value x can be
In
obtained for yi=73.
73
SHIFT
Ans
Copyright L
2002
EXIBOOK
A
EXE
B
EXE
R
EXE
y
EXE
SHIFT
x
EXE
R
x
2
EXE
-
R
ALPHA
W
y
x
x
SHIFT
SHIFT
÷
(
W
-
ALPHA
EXE
1003 is entered, enter correct data after pressing
1003
is entered, enter correct data after pressing
DT
1003
is entered previously, enter correct data after pressing 11
DT
.
^
^
y - A
^
x = exp
B
^
^
SHIFT
X
EXE
SHIFT
and Σxy are obtained by Σlnx, Σ(lnx)
2
Key Operation
÷
Scl
EXE
,
29
1.6
SHIFT
DT
,
50
23.5
SHIFT
DT
,
74
38.0
SHIFT
DT
,
103
46.4
DT
SHIFT
,
118
48.9
SHIFT
DT
A
EXE
B
EXE
R
EXE
80
^
y
SHIFT
EXE
x
^
EXE
SHIFT
e
x
EXE
997.4
Constant term A.
0.56
Regression coefficient B
0.982607368
Correlation coefficient r
1007.48
Length at 18º C.
4.642857143
Temperature at 1000mm
0.965517241
35.
Covariance
1003
)
,
SHIFT
DT
.
AC
.
CL
SHIFT
^
x
is used, and to
^
y
in
SHIFT
EXE
is used.
Ans EXE
e
x
, and Σlnx.y respectively.
2
Display
Remark
Clear memory
3.36729583
3.912023005
4.304065093
4.634728988
4.770684624
-111.1283976
Constant term A
34.02014748
Regression coefficient B
0.994013946
Correlation coefficient r
^
37.94879482
y when xi=80
^
224.1541314
x when yi=73
- 35 -
GB
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