Probability Rules

Probability is the chance of an event that may or may not occur. For those events, understanding the probability rules and predicting the likelihood of those events will erase the serious harms or threats that may occur in the future.

Such as investors in the stock market where they analyze the future outcomes of stock market rates and in weather forecasting, where they predict the weather changes and harmful events that may occur in the future, etc.
 

There are specific rules and conditions probability follows that will help us calculate the chances of different events happening. Understanding these rules will eliminate risks in predicting future events. Let’s understand all those rules:

Addition Rule:

If an event happening is a union of two events, let’s say event A and event B. Then the probability of that event happening is represented by 

    P (A ⋃ B) = P (A) + P (B) – P (A ∩ B)

Multiplication Rule:

If there is an intersection between two other events, say A and B. Then both events occurring or the probability of those two events occurring together is represented by

    P (A ∩ B) = P (A) × P (B)

Complement Rule:

If A is an event, then the chance that the event won't happen, or that A's complement, is given by

    P (A’) = 1 – P (A)

Conditional Rule:

If we already know that event A has happened, and we want to find the probability of event B happening, we use a special rule. This rule says that:

    P (A/B) = P (A ∩ B) / P (B)
 

Probability is not just about numbers, or we can say that probability is not only used in mathematics. It is used in everyday life while playing games, weather forecasting, business etc. Let’s understand some real-life applications of probability. 

• Weather forecasting uses probability rules to predict the future weather conditions of an area.
  
   
• We use probability for rolling a die in board games. For example, the chance of getting a 6 is 1 out of 6. Since a die has 6 sides, its probability will be ⅙. 
  
   
• In flipping a coin, probability is used. But unlike a die, its probability will always be either Heads or Tails.
  
   
• Probability is also used while drawing a card from a deck of 52 cards. For example, the chance of drawing an Ace from the deck of 52 cards is 4/52, because there are 4 Aces in a deck of cards.