2 The random variable \(X\) has probability generating function \(\mathrm { G } _ { X } ( t )\) given by
$$\mathrm { G } _ { X } ( t ) = \frac { 1 } { 5 } + p t + q t ^ { 2 }$$
where \(p\) and \(q\) are constants.
- Given that \(\mathrm { E } ( X ) = 1.1\), find the numerical value of \(\operatorname { Var } ( X )\).
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The random variable \(Y\) has probability generating function \(\mathrm { G } _ { Y } ( t )\) given by
$$\mathrm { G } _ { Y } ( t ) = \frac { 2 } { 3 } t \left( 1 + \frac { 1 } { 2 } t ^ { 2 } \right)$$
The random variable \(Z\) is the sum of independent observations of \(X\) and \(Y\). - Find the probability generating function of \(Z\).
- Find \(\mathrm { P } ( Z > 2 )\).
- State the most probable value of \(Z\).