5-12
Cubic regression
Model formula .......
y = ax
3
+ bx
2
+ cx + d
a
..........regression third coefficient
b .......... regression second coefficient
c .......... regression first coefficient
d .......... regression constant term
(
y-intercept)
Quartic regression
Model formula .......
y = ax
4
+ bx
3
+ cx
2
+ dx + e
a
..........regression fourth coefficient
b .......... regression third coefficient
c .......... regression second coefficient
d .......... regression first coefficient
e .......... regression constant term ( y-intercept)
k Logarithmic Regression Graph
Logarithmic regression expresses y as a logarithmic function of x. The standard logarithmic
regression formula is y = a + b × In x, so if we say that X = In x, the formula corresponds to
linear regression formula y = a + bX.
1(CALC)6(g)2(Log)
6(DRAW)
The following is the logarithmic regression model formula.
y = a + b·ln x
a
..............regression constant term
b .............. regression coefficient
k Exponential Regression Graph
Exponential regression expresses y as a proportion of the exponential function of x. The
standard exponential regression formula is y = a × e
bx
, so if we take the logarithms of both
sides we get In y = In a + bx. Next, if we say Y = In y, and A = In a, the formula corresponds to
linear regression formula Y = A + bx.
1(CALC)6(g)3(EXP)
1(
aeˆbx) or 2(abˆx)
6(DRAW)
The following is the exponential regression model formula.
y = a·e
bx
a ..............regression coefficient
b ..............regression constant term
y = a·b
x
a ..............regression constant term
b ..............regression coefficient
Quadratic regression
Model formula .......
y = ax
2
+ bx + c
a
..........regression second coefficient
b .......... regression first coefficient
c .......... regression constant term
( y-intercept)
