Find the mean and variance of the number of tails on the throw of three coins.

Find the mean and variance of the number of heads on the throw of three coins.

Find the mean and variance of the number obtained on a throw of an unbiased die.

A dice is thrown thrice. Find the mean and variance of the number of times a 'six' is obtained.

Find the mean and variance of the first n natural numbers.

Find the variance of the number obtained on a throw of an unbiased die.

Find the mean and variance of the probability distribution of the number of sixes in three tosses of a die.

Find the probability distribution of the number of tails when three coins are tossed simultaneously.

An unbiased coin is tossed 4 times. Find the mean and variance of the number of heads obtained.