2 The curve \(C\) has equation \(y = 2 x ^ { \frac { 1 } { 2 } }\) for \(0 \leqslant x \leqslant 4\). Find
- the mean value of \(y\) with respect to \(x\) for \(0 \leqslant x \leqslant 4\),
- the \(y\)-coordinate of the centroid of the region enclosed by \(C\), the line \(x = 4\) and the \(x\)-axis.