Question 1047561
1.  X may assume 0,1,2,3
2. 3 will occur most often, because the probability is greatest.
3.  The probability x will be greater than 0 is 0.9, because probability of 0 is 0.1 and that is the only probability excluded.
4. E(x)=x*p(x)=
0*0.1+1*0.2+2*0.3+3*0.4=0+0.2+0.6+1.2=2.
E(x)=2
5.V(x)=0.4+0.2+0+0.4=1.0, again as you had.
6. 0.75 is the sum of the other probabilities.  The probability of x's being 15 is 0.25.
7. Correct as you had it.
8.Slightly skewed.  It isn't symmetric, so skewed it must be.
9.Expected value is 16.75 The value of 15 has probability 0.25, so it contributes 3.75 to the sum.
10. (5-16.75)^2*0.15=20.709375
(10-16.75)^2*0.10=4.55625
(15-16.75)^2*0.25=0.765625
(20-16.75)^2*0.25=2.640625
(25-16.75)^2*0.25=17.015625
Sum is 45.6875