# matrix multiplication

1. ### Differentiation Involving Determinant.

I have to compute the following differentiation : \frac{\partial}{\partial\sigma^2}\det[\mathbf X_{p\times n}'(\sigma^2 \mathbf I_{n}+\mathbf Z_{n\times q}\mathbf G_{q\times q}\mathbf Z_{q\times n}')^{-1}\mathbf X_{n\times p}], where \sigma^2 is a scalar, \det denotes determinant, \mathbf...
2. ### Matrix Multiplication + Save Result by group

Bonjour a tous, I'm trying to achieve the following multiplication VAR = W*S*W' w: [n,1] S: [n,n] s: [n,1] I have the following variables in Stata: date W s In my case, S is a square matrix [n,n] with 1 in the diagonal and a constant (per period) "s" in the diagonal. The...
3. ### Help! I'm so lost with this one!

I've tried to see if I can find examples of this question to help me, but I can't please help. The top four teams in the Big West Hockey Leagues have just completed the first half of their season. Each team has played 20 games. The teams statistics are listed in the following table. Each team...