The distribution function $$F(X)$$ of discrete random variable $$X$$ is given by

Then $$\mathrm{P[X=4]+P[x=5]=}$$

First bag contains 3 red and 5 black balls and second bag contains 6 red and 4 black balls. A ball is drawn from each bag. The probability that one ball is red and the other is black, is

A fair coin is tossed 4 times. If $$X$$ is a random variable which indicates number of heads, then $$\mathrm{P}[\mathrm{X}<3]=$$

If the mean and variance of a binomial distribution are 4 and 2 respectively, then probability of getting 2 heads is