4. Explain what you understand by
- a sample space,
- an event.
Two events \(A\) and \(B\) are independent, such that \(\mathrm { P } ( A ) = \frac { 1 } { 3 }\) and \(\mathrm { P } ( B ) = \frac { 1 } { 4 }\).
Find - \(\mathrm { P } ( A \cap B )\),
- \(\mathrm { P } ( A B )\),
- \(\mathrm { P } ( A \cup B )\).