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9
Matrices and Linear Algebra
So far, we have dealt with one variable, or a series of identical variables (stationary process), and
in the case of regression with two variables. In the remainder of the book, we study methods of
analysis with several or many variables, say X
1
, X
2
, …, X
n
, where n is the dimension of the system.
Because we need to solve the equations simultaneously, we use mathematical strategies that take
advantage of the relationships among the variables to nd a solution. A very useful strategy is to
arrange the interactions among the variables in an array called matrix.
More specically, when the interactions among the var ...