My understanding of linear independance is that if you have a unique solution after rref, it's linear independant. If you have multiple solutions or no solution, it's not linear ...

Journal of the Royal Statistical Society. Series B (Statistical Methodology), Vol. 75, No. 2 (MARCH 2013), pp. 323-343 (21 pages) The paper is concerned with inference for linear models with fixed ...

The Canadian Journal of Statistics / La Revue Canadienne de Statistique, Vol. 22, No. 2 (Jun., 1994), pp. 219-231 (13 pages) We consider the problem of robust M-estimation of a vector of regression ...