For a random vector $\displaystyle \b{X} = X_1,X_2,X_3,X_4 $

I am given only $\displaystyle \bar{\b{X}}$ a 4x1 matrix and $\displaystyle \b{S}$ a 4x4 matrix.

I am asked to find the total mean and variance for $\displaystyle \b{X} $

I know for the variance I need to find $\displaystyle |\b{S}|$ but how do I find the total mean?