2.Find the variance and standard deviation of the probability distribution of the random variance X, which can take only the values 3,5, and 7, given that P(3)=7/30, P(5)=1/3, and P(7)=13/30. 4.Find the variance and standard deviation of the probability distribution of the random variable X if P(X)=(x+1)/20 for X=1,2,3, 4, and 5