Module 1:Concepts of Random walks, Markov Chains, Markov Processes
  Lecture 1:Introduction to Stochastic Process
 

We already know that if  is the random variable (r.v), such that , , then  is the distribution function of the random variable (r.v) . Consider a finite collection of random variables (r.v's) in , where . Then the joint distribution of  is given by . In case  are independent, we have
.

In case they are independent and identically distributed, then the following is true. For example  and  are
independent but not identical, while  and  are independent and identical, i.e., i.i.d.