sand dollar. n. 1. Any of various thin circular echinoderms of the order Clypeasteroida, especially Echinarachnius parma, of coastal northern Atlantic and Pacific waters, having a covering of short movable spines.
One reason why linear algebra is very useful is that linear transforms of normal variables are normal. If x ~ N(a, A), then Bx+b ~ N(Ba+b, BABT). In a way, when everything is linear and normal, everything is nice and analytically tractable.
Particularly, linear algebra will be heavily used in your multivariable statistics course(s). Some matrix algebra will also be very convenient for your potential studies in Markov chains and stochastic processes. Linear regression is of course a very common use of linear algebra as well.