Random Variables

A random variable, say X, is an outcome of an experiment. The outcome will vary when the experiment is repeated. The outcome could be influenced by external factors, which are called exogenous variables of the experiment. 

Suppose, ; the value of X is 2. This value will be constant, irrespective of any factors. In this case, is not a random variable. A random variable should have the ability to attain a varying value.

Let’s understand the random variables with examples. 

Example1: Suppose tossing a coin is an experiment. Then the outcome would be head or tail. The outcome is a random variable, as the outcome varies with the experiment.

Example2: Choosing a restaurant to dine in. The outcome would vary from individual to individual and also with time. 

Example3: Marks obtained in an exam. 

These Random Variables can be classified into various types based on their characteristics. Please see Types of Random Variables.