Let \(X_1\) and \(X_2\) be the numbers on two independent fair-die rolls. Let \(M\) be the maximum and \(N\) the minimum of \(X_1\) and \(X_2\). Calculate:

1. \(\mathbf{E}( M| N=x) \)
2. \(\mathbf{E}( N| M=x) \)
3. \(\mathbf{E}( M| N) \)
4. \(\mathbf{E}( N| M) \)