Sometimes it happens that during rainy season, you carry a raincoat every day and it does not rain for many days. However, by chance, one day you forget to take the raincoat and it rains heavily on that day.
You face a lot of situations such as these where you take a chance and it does not go the way you want it to. These are examples where the chances of a certain thing happening or not happening are not equal.
Getting a result :
Imagine that you are the captain of one team and your friend is the captain of the other team. You toss a coin and ask your friend to make the call. Can you control the result of the toss? Can you get a head if you want one? Or a tail if you want that? No, that is not possible. Such an experiment is called a random experiment. Head or Tail are the two outcomes of this experiment.