Answer:
Expected value =0.9
Standard deviation = 0.4359
Step-by-step explanation:
Let's use the formula to find expected value or mean.
Expected value =Σ x *P(x)
 x   0   1   2
P(x) ) .15 Â .8 Â .05
So, expected value = (0)(0.15) +1(0.8)+2(0.05)
                = 0 +0.8 +0.1
                =0.9
Expected value =0.9
Now, let's find standard deviation
x      [tex](x- E(x))^{2}[/tex]     [tex](x-E(x))^{2} *p(x)[/tex]
0 Â Â Â Â Â [tex](0-0.9)^{2}[/tex] Â Â Â Â Â Â [tex](0-0.9)^{2} *0.15[/tex] Â =0.1215
1 Â Â Â Â Â Â [tex](1-0.9)^{2}[/tex] Â Â Â Â Â Â [tex](1-0.9)^{2} *0.8[/tex] Â Â =0.008
2 Â Â Â Â Â [tex](2-0.9)^{2}[/tex] Â Â Â Â Â Â [tex](2-0.9)^{2} *0.05[/tex] Â =0.0605
Now, add the last column together and then take square root to find standard deviation.
Standard deviation of the distribution =[tex]\sqrt{0.1215+0.008+0.0605)}[/tex]
Simplify it, so standard deviation =0.4358898...
Round the answer to nearest four decimal places
Standard deviation = 0.4359