These are questions to address understanding of R commands in relation to matrices
Novice to competent question:
Which command returns the second to last element in a 2×2 matrix (X)?
A) X[-1,-1]
B) X[2,2]
C) X[-c(1:3)]
D) X[-2,-2]
Competent to expert question:
Given: X<-matrix(nrow=x,ncol=y)
Which choice does not equal x*y?
A) length(t(X))
B) (dim(X)*dim(X)-dim(X)[2])[2]
C) (dim(X)*dim(X)-dim(X)[2])[1]
D) (dim(t(X))*dim(t(X))-dim(t(X))[1])[1]