 Hello and welcome to the session. In this session we will discuss probability. Here we will learn how to measure the chance of occurrence of a particular outcome in an experiment. An operation which can produce some well-defined outcomes is called an experiment. Using a coin for an experiment, let's see what is a trial. A trial is an action which results in one or several outcomes. When we toss a coin, then in that case each toss of a coin would be a trial. Let's define an event. An event for an experiment is the collection of some outcomes of the experiment. Like when we toss a coin in that experiment, getting a head with outcome, head is an event. And also, getting a tail with outcome, tail is also an event for the experiment of tossing a coin. Now let's see what probability is. Empirical probability of an event e happening denoted by p e is equal to number of trials in which the event happened upon the total number of trials. The empirical probability depends on the number of trials undertaken and the number of times the outcomes you are looking for coming up in these trials. And probability of an event e that is p e lies between 0 and 1 that is it is greater than or equal to 0 and less than or equal to 1. Suppose that a coin is tossed 200 times with the falling frequency for head, it's 114 that is head comes up 114 times and tail comes up 86 times. We need to find the probability for each event. Consider e to be an event of getting a head and f be an event of getting a tail. Now probability of getting a head is given by p e this is equal to number of heads coming up that is 114 upon the total number of trials and that is 200. This comes out to be equal to 0.57 so probability of getting a head is 0.57. Now probability of getting a tail is given by p f this is equal to number of tails coming up and that is 86 upon the total number of trials that is 200. Which is equal to 0.43 so probability of getting a tail is 0.43. This is how we can find the empirical probability or the experimental probability for any event. This completes this session. Hope you have understood the concept of probability.