Last updated on June 5th, 2025
Independent events are the events that occur together, but the outcome of one event does not affect the outcome of the other in any manner. In this topic, we are going to talk about independent events and how they are different from dependent events.
Two events are said to be independent events if the result of one event does not impact the result of another event. In math, we would say that the outcome of one event does not impact the probability of another event, this is what we call independent events. One such example would be winning the lottery and going on a picnic. Both events do not influence the other, making this an independent event.
We usually show the probability of independent events with the formula:
P(A ∩ B) = P(A) × P(B)
If two events A and B are independent, then the probability of both events happening is equal to A ∩ (and) B
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Probability has two types of events: Independent events and dependent events. Here are a few differences between the two events:
Independent Events | Dependent Events |
When two events do not impact the probability of each other's outcome, we call it independent events. | The occurrence of one event affects the probability of another event. |
Example: Watching a movie on your laptop and booking a cab. | Example: Drawing twp cards from a deck without replacement |
Formula: P(A and B) = P(A) × P(B) |
Formula: P(A and B) = P(A) × P(B after A) |
When learning about independent events there are a few certain rules that must be followed such as:
We use this rule to find the probability of any events that occur simultaneously. The rule of multiplication is expressed as P(A ∩ B) = P(A) × P(B)
The rule of addition allows us to determine the probability if at least one of the events occurs. It is expressed as (A ∪ B) = P(A) + P(B) - P(A ∩ B)
To find the probability of independent events, we use a formula:
P(A and B) = P(A) × P(B)
Where:
P(A and B) is the probability that both events occur
P(A) is the probability of event A.
P(B) is the probability of event B
If these statements are true, then A and B are independent events.
Step 1: Calculate the individual probabilities so first, we find the probability of P(A) and then the probability of P(B)
Step 2: Then we calculate the joint probability, which is P(A and B)
Step 3: Determine whether it is independent or not by using the formula P(A and B) = P(A) × P(B). If it is not true, then events are dependent.
We know how to find the probability of independent events, but we need to first identify whether an event is independent or not:
There are many uses of independent events. Let us now see the uses and applications of independent events in different fields:
We use independent events in sports where in football, the coin toss at the start of the game is independent of the match’s outcome. Each toss has a 50% chance of landing heads or tails, no matter what happened before.
We use the concept of independent events in games like Monopoly or Yahtzee, where rolling a die is independent of the previous rolls. The probability of rolling 6 remains 1/6 on each throw.
We use the concept of independent events in lottery draws and gambling, where each lottery ticket has an equal chance of winning, independent of the previous draws. In a roulette game, the ball landing on red is independent of past spins.
When understanding the concept of independent events, students tend to make mistakes. Here, are some common mistakes and their solutions
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What is the probability of getting heads on the first toss and tails on the second toss?
0.25
P(Heads) = 0.5
P(Tails) = 0.5
We use the formula: P(A and B) = P(A) × P(B)
P(Heads and Tails) = 0.5 × 0.5 = 0.25
The probability of getting heads on the first toss and tails on the second toss is 0.25
What is the probability of getting tails on a coin toss and a 4 on a die roll
1/12 or 0.0833 (approximately)
P(Tails) = ½ = 0.5
P(4 on a die) = 1/6 ≈ 0.1667
We use the formula: P(A and B) = P(A) × P(B)
P(Tails and 4 on a die) = 1/2 × 1/6 = 1/12
What is the probability of drawing an Ace from a standard 52-card deck and rolling a 6 on a die?
1/78
P(Ace) = 4/52 = 1/13
P(6 on a die) = 1/6
We use the formula: P(A and B) = P(A) × P(B)
P(Ace and 6 on a die) = 1/13 × 1/6 = 1/78
What is the probability of rolling a 2 on the first roll and a 4 on the second roll with a die?
1/36
P(2 on a die) = 1/6
P(4 on a die) = 1/6
We use the formula: P(A and B) = P(A) × P(B)
P(2 on a die and 4 on a die) = 1/6 × 1/6 = 1/36
What is the probability of rolling an even number and drawing a red card from a standard deck (there are 26 red cards out of 52)?
0.25
P(even number on die) = 3/6 = 0.5
P(Red card) = 26/52 = 0.5
We use the formula: P(A and B) = P(A) × P(B)
P (even number on die and red card) = 0.5 × 0.5 = 0.25.
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Jaipreet Kour Wazir is a data wizard with over 5 years of expertise in simplifying complex data concepts. From crunching numbers to crafting insightful visualizations, she turns raw data into compelling stories. Her journey from analytics to education ref
: She compares datasets to puzzle games—the more you play with them, the clearer the picture becomes!