Biometrical Letters vol. 47(2), 2010, pp. 155-159


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A SIMPLE ALGEBRAIC DERIVATION OF NORMAL EQUATIONS

Czesław Stepniak

Institute of Mathematics, University of Rzeszów, Rejtana 16 A, 35-959 Rzeszów,
Poland, e-mail: cees@univ.rzeszow.pl


Normal equations have a nice geometric interpretation but their formal derivation requires some mathematical knowledge, such as differential calculus or generalized inverse. We present a simple algebraic method based on the equivalence of certain systems of linear equations. This equivalence may be interesting in itself.


system of linear equations, equivalent systems, least squares solution, normal equations.