The random variable X is the amount of syrup prescript by a physician.
Then the random variable is

Discrete random variable

Mean of a discrete random variable

Number of floors in a building. Then the random variable is

Variance of random variable

Let a pair of dice he rolled thrice and the random variable X be the number of doublets. Find the mean of the random variable.

Let a pair of dice he rolled thrice and the random variable X be the number of doublets. Find the mean of the random variable.

Variance of a discrete random variable

If a RV X="Height of a sky scrapper" Then the random variable is

A person on a high protein diet is interested in the random variable X, the gain in weight in a week. Then the random variable is

A random variable X has the following distribution