Let a pair of dice be thrown and the random variable X be the sum of the numbers that appear on the two dice. Find the mean (or expectation) of X.

A pair of dice is tossed once and X denotes the sum of numbers that appears on the two dice, then P(Xle4)=______ .

A pair of dice is thrown. Find the following event : The sum is 7.

Two dice are thrown together. What is the probability that the sum of the numbers on the two faces is greater than 8 ?

Two dice are thrown together. What is the probability that the sum of the numbers on the two faces is neither 9 nor 11 ?

There are 5 cards numbered 1 to 5, one number on one card. Two cards are drawn at random without replacement. Let X denote the sum of the numbers on the two cards drawn. Find the mean and variance of X.

A pair of dice is thrown. Find the following event : The sum is greater than 10.

A pair of dice is thrown. Find the probability of getting a doublet.

Let X denote the sum of the numbers obtained when two fair dice are rolled. Find the variance and standard deviation of X.