The SURVEYMEANS Procedure
A Hadamard matrix 
is a square matrix whose elements are either 1 or –1 such that
![\[ \mb {H}\mb {H}’=k\mb {I} \]](images/statug_surveymeans0244.png){kind=small}
where k is the dimension of and 
is the identity matrix of order k. The order k is necessarily 1, 2, or a positive integer that is a multiple of 4.
For example, the following matrix is a Hadamard matrix of dimension k = 8:
![\[ \begin{array}{rrrrrrrr} 1 & 1 & 1 & 1 & 1 & 1 & 1 & 1\\ 1 & -1 & 1 & -1 & 1 & -1 & 1 & -1\\ 1 & 1 & -1 & -1 & 1 & 1 & -1 & -1\\ 1 & -1 & -1 & 1 & 1 & -1 & -1 & 1\\ 1 & 1 & 1 & 1 & -1 & -1 & -1 & -1\\ 1 & -1 & 1 & -1 & -1 & 1 & -1 & 1\\ 1 & 1 & -1 & -1 & -1 & -1 & 1 & 1\\ 1 & -1 & -1 & 1 & -1 & 1 & 1 & -1 \end{array} \]](images/statug_surveymeans0246.png)