x ------ 1 ------- 2 -------3-------- 4------ 5

P(X=x) .18----- .22 -------.35------ a ------.13

need some help in solving this

not the answer jus the steps

i solved a already

a=.12

find the value of a

find the mean of the random variable X

find the value of the E(X^2)

find the variance the the random variable X

find the standard deviation of the random variable X