7 The random variable \(X\) has probability density function f given by
$$\mathrm { f } ( x ) = \begin{cases} 0.2 \mathrm { e } ^ { - 0.2 x } & x \geqslant 0
0 & \text { otherwise } \end{cases}$$
- Find the distribution function of \(X\).
- Find \(\mathrm { P } ( X > 2 )\).
- Find the median of \(X\).