suppose that the probability mass function for discrete r.v. X is

x: -1 0 1 3

P(x): 0.1 0.5 a 0.2

a) find the value of a

b)P(X1)=

c) the mean of random variable XE(X)=

d) find the expected value ofg(x)=x^2

that isE(g(X))=E(X^2)=