Nothing in life is certain and there is always an element of chance, so there is randomness everywhere around us.
Let’s say a person wants to go to the supermarket and he would like to know the chance that he would get infected with COVID
There is no definite answer to this question and the reason for that is the random nature of the world around us
Let’s try to ask a few questions to understand what randomness means:
- What is the mode of transport for going to the supermarket? Private vehicle or public transport. Now this decision itself introduces some randomness because on one hand, taking public transport could be riskier as there would be more people but there is no guarantee that you’ll encounter more people, it is possible that everyone thinks that public transport is risky and no one goes there and hence if you end taking public transport then you might not encounter many people. On the other hand, while taking the private vehicle seems less risky but it had the same idea, then in the parking lot of the mall, super-market, it’ll be very crowded over there. So, there are a lot of possibilities here and we can not say anything for certain because we do not know what is going to happen there and that brings in the uncertainty.
- If we take the immune system of the person going to the supermarket, we can ask if this person is more immune, did he have a certain strain of coronavirus earlier or he had some vaccinations which he took in his childhood which we don’t know yet and because of that the person is more immune, does the person do some yoga on a daily basis, some physical exercise which might strengthen his immune system and so on, so the answers to all these questions vary from person to person and that brings in the randomness.
- Does this person have co-morbidities? If yes, then how severe are they on a scale of 0–1, in the past few months had the person brought the co-morbidity under control or not. The answer to these questions vary from person to person and this again brings in the uncertainty.
- How many infections are there in the person’s neighborhood? If the infection rate in the community is lower, then the person need not worry much, whereas if the infection rate is higher then the answer will change. So, this again brings in some randomness.
And this randomness is not limited to the pandemic scenario, it is present in all the domains we look around for example in the sports domain in the game of cricket, there is always a chance that the batsman might hit six 6's in the last over and that may change the outcome of the game and in fact, this element of chance is what keeps us excited about sports.
In the domain of finance, there is an element of chance in the stock market.
Same for the agriculture domain, we can not say with certainty that all the farms in a given district will produce similar output in terms of yield per acre, there are multiple factors in this result, how good are the workers in a farm, how knowledgeable is the farmer, how goods are the seeds, if the water supply is good or not and so on.
Similarly, in the case of vaccines, we need to test it because there is this element of chance that it might not work on a certain age group, maybe it might not work on people with some medical condition, and so on.
So, in all the domains we have this element of chance and that’s why the probability theory plays a very important role as we want to model this element of chance, we want to make statements of the form that a vaccine will work effectively on a person with so and so conditions.
This element of chance comes under probability theory and is present in all the domains.