The discrete random variable \(X\) has probability distribution
\(x\)
- 2
- 1
0
1
3
\(\mathrm { P } ( X = x )\)
0.25
\(a\)
\(b\)
\(a\)
0.30
where \(a\) and \(b\) are probabilities.
Find \(\mathrm { E } ( X )\)
Given that \(\operatorname { Var } ( X ) = 3.9\)
find the value of \(a\) and the value of \(b\)
The independent random variables \(X _ { 1 }\) and \(X _ { 2 }\) each have the same distribution as \(X\)
Find \(\mathrm { P } \left( X _ { 1 } + X _ { 2 } > 3 \right)\)