What is Random Variable?

Random Variable:

When there is a probability associated with a variable that makes it Random Variable.
So a Random variable can take many different values with different probabilities.


Q.1) No. of Days in a week-: Is this a Random Variable?

A.1)  NO, because no. of days in a week is fixed i.e 7

Q.2) No. of Days in a Month-: Is this a Random  Variable?

A.1)  Yes, because no. of days in a month can be 28,29,30 or 31. So this is Random in nature.


Suppose X is "Something" now it can take value "0" if 3 comes up on a Dice and "1" if even no. comes up on dice.

So we know that probability of getting a 3 on Dice is 1/6 . So probability of getting a value "0" is 1/6
Similarly the probability of getting an Even no. on dice is 1/2. So probability of getting "1" is 1/2.

so we see that when "something is attached with different values along with different probabilities it becomes a Random variable.



  1. Thankyou for sharing this wonderful article. But I have a doubt~is Random Variable- a variable to which probability is associated? Random variable is a value associated with a random experiment. In that is there really a role of probability? Because in the example you mentioned no. of days in a month can be 28,29,30& 31. There is no probability. It is all about values. Please share your thoughts on this. Thankyou!


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