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View Full Version : Study Note 7P-27-00 (7 Pre-test)

rhoucag
04-01-2002, 06:36 PM
I'm having trouble with the matrix arthimetic on pages 506 and 508.
(Study Note 7P-27-00)

Does anyone know the dimensions of V(B) ? (greek B)
Also, what are the dimensions of X used in the definition of V(B)?
Dimensions for y, defined top of page 506.

I'm guessing for X , ( s * k + l + m ).
For y , ( s ^2 * 1 ).

Actually I can't reconcile the multiplication in V(y) formula. ( bottom page 508).

Here goes:
Assum that X is ( a * b ) dimension wise.

Then V(B) will be (b * b ).
Take a look at the formula for V(y) on bottom of page 508.
You are multiplying X' by V(B).
This is ( b * a ) X ( b * b ) dimension wise.

And since the cols of first must equal the rows of the second, this is not valid matrix arithmetic.

Have I done something wrong ? Is there an error in the Study Note ?

Also, X is defined as ( x'(1,0), ... , x'(s,0) ).
Where do the others go ? i.e. x'(1,1) or x'(2,3) ?
x'(w,d) is defined in middle of page 505.

Thanks for any help in advance.

Charlie