Probability Distributions of a Random Variable
This chapter begins by focusing on the concept of a random variable. A random variable is of course a variable but with an additional property. A variable is said to be random when it is not known which of its values it will take on next.
For example:
Let the variable X be the number obtained on one roll of a fair die.
X =[ 1,2,3,4,5,6]
X is said to be a random variable because it is not known which of its possible six values it will take on, on the next roll of the die
Definition
A random variable is a variable which takes on its values by chance.
You will recall from chapter I that variables may be classified as either discrete or continuous. Random variables are either discrete or continuous. The random variable X from the previous example would be classified as a discrete random variable.
A probability distribution of a random variable is an assignment of probabilities to the values of a random variable.