I was asked about possible reference books to learn
more about linear/matrix algebra and statistics.
Some references you might consider:
Strang, G. 1976. Linear Algebra and Its Applications. QA 184 .S8Searle, S.R. 1982. Matrix Algebra Useful for Statistics. QA188 .S4 1982
Graybill, F.A. 1983. Matrices With Applications in Statistics, 2nd Ed. QA188 .G715 1983
Healy, M.J.R. 1986. Matrices for Statistics. QA188 .H43 1986
Schott. J.R. 1997. Matrix Analysis for Statistics.