S3-SA3-0280
What is the Probability of Sure Event?
Grade Level:
Class 8
AI/ML, Data Science, Physics, Economics, Cryptography, Computer Science, Engineering
Definition
What is it?
The probability of a sure event is 1. A sure event is an event that will always happen, no matter what. It's an outcome that is guaranteed to occur.
Simple Example
Quick Example
Imagine you have a bag full of only red ladoos. If you pick a ladoo from the bag, what is the probability that you will pick a red ladoo? It's a sure event, so the probability is 1.
Worked Example
Step-by-Step
Let's say you have a standard six-sided dice. What is the probability of rolling a number less than 7? --- Step 1: Identify all possible outcomes when rolling a dice. The outcomes are {1, 2, 3, 4, 5, 6}. So, the total number of possible outcomes is 6. --- Step 2: Identify the favourable outcomes for rolling a number less than 7. These are {1, 2, 3, 4, 5, 6}. So, the number of favourable outcomes is 6. --- Step 3: Use the formula for probability: Probability = (Number of Favourable Outcomes) / (Total Number of Possible Outcomes). --- Step 4: Substitute the values: Probability = 6 / 6. --- Step 5: Calculate the probability: Probability = 1. --- Answer: The probability of rolling a number less than 7 is 1.
Why It Matters
Understanding sure events helps in fields like Data Science to predict certain outcomes. In Physics, it helps determine the certainty of experiments. Even in AI/ML, it's foundational for building models that predict events with high confidence, leading to better technology like self-driving cars.
Common Mistakes
MISTAKE: Thinking the probability of a sure event can be greater than 1. | CORRECTION: Probability values always range from 0 (impossible) to 1 (sure). It can never be more than 1.
MISTAKE: Confusing a highly probable event with a sure event. | CORRECTION: A highly probable event might have a probability like 0.99, but a sure event *must* have a probability of exactly 1.
MISTAKE: Believing a sure event means 'very likely to happen'. | CORRECTION: A sure event means it *will definitely* happen, with absolutely no doubt.
Practice Questions
Try It Yourself
QUESTION: What is the probability that tomorrow will follow today? | ANSWER: 1
QUESTION: A box contains 10 blue pens. What is the probability of picking a blue pen from the box? | ANSWER: 1
QUESTION: You flip a fair coin. What is the probability that the coin will either land on heads or tails? | ANSWER: 1
MCQ
Quick Quiz
Which of the following events has a probability of 1?
Rolling an even number on a standard six-sided dice.
Picking a red ball from a bag containing 5 red and 5 blue balls.
The sun rising in the east.
Getting a score of 100% on a surprise test.
The Correct Answer Is:
C
The sun rising in the east is a natural phenomenon that is guaranteed to happen, making it a sure event with a probability of 1. The other options are not guaranteed.
Real World Connection
In the Real World
Think about weather forecasting apps like AccuWeather or Google Weather. While they often predict probabilities (like a 70% chance of rain), if the forecast says there's a 100% chance of the sun rising tomorrow, that's a sure event. Similarly, if a delivery app like Swiggy confirms your order is 'placed' and 'paid', it's a sure event that your order has entered their system.
Key Vocabulary
Key Terms
PROBABILITY: The likelihood of an event happening | SURE EVENT: An event that is certain to occur | OUTCOME: A possible result of an experiment | CERTAINTY: The state of being definitely true or sure
What's Next
What to Learn Next
Great job understanding sure events! Now, you should explore 'What is the Probability of an Impossible Event?'. It's the opposite of a sure event and will help you understand the full range of probability values from 0 to 1.


