Least-squares using successive rows – HP 15c User Manual

Page 118

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118

Section 4: Using Matrix Operations

118

6.963636364

b

1

estimate.

´U

6.963636364

Deactivates User mode.

´•4

6.9636

The Reg SS for the PPI variable adjusted for the constant term is

(Reg SS for reduced model) − (Reg SS for constant) = 51.29864900.

The Reg SS for the UR variable adjusted for the PPI variable and the constant term is

(Reg SS for full model) – (Reg SS for reduced model) = 3.274630500.

Now construct the following ANOVA table:

Source

Degrees of

Freedom

Sum of

Squares

Mean Square

F Ratio

UR | PPI, Constant

1

3.2746305

3.2746305

1.939

PPI | Constant

1

51.2986490

51.2986490

30.37

Constant

1

533.4145457

533.4145457

315.8

Residual (full model)

8

13.5121750

1.68902188

Total

11

601.5000002

The F ratio for the unemployment rate, adjusted for the producer price index change and the
constant is not statistically significant at the 10-percent significance level (α = 0.1). Including
the unemployment rate in the model does not significantly improve the CPI fit.

However, the F ratio for the producer price index adjusted for the constant is significant at
the 0.1 percent level (α = 0.001). Including the PPI in the model does improve the CPI fit.

Least-Squares Using Successive Rows

This program uses orthogonal factorization to solve the least-squares problem. That is, it
finds the parameters b

1

, …, b

p

that minimize the sum of squares

)

(

)

(

||

||

2

Xb

y

Xb

y

r

T

F

given

the model data

n

np

n

n

p

p

y

y

y

x

x

x

x

x

x

x

x

x

2

1

2

1

2

22

21

1

12

11

and

y

X

.

The program does this for successively increasing values of n, although the solution b = b

(n)

is meaningful only when n ≥ p.

It is possible to factor the augmented n × (p + 1) matrix [X y] into Q

T

V, where Q is an

orthogonal matrix,

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