Edexcel GCSE Foundation Maths: What is Probability?
Probability is a way of measuring how likely something is to happen. It's expressed as a fraction, decimal or percentage between 0 and 1 (or 0% and 100%).
Here's a breakdown:
- 0 (or 0%) means something is impossible. For example, the probability of flipping a coin and getting 3 heads is 0.
- 1 (or 100%) means something is certain. For example, the probability of the sun rising tomorrow is 1.
- Values between 0 and 1 (or 0% and 100%) represent different levels of likelihood. For example, the probability of flipping a coin and getting heads is 0.5 (or 50%).
Here's how to calculate probability:
- Identify the total number of possible outcomes. For example, if you roll a die, there are six possible outcomes (1, 2, 3, 4, 5, 6).
- Identify the number of favorable outcomes. For example, if you want to know the probability of rolling a 3, there is one favorable outcome.
- Calculate the probability by dividing the number of favorable outcomes by the total number of possible outcomes. In this case, the probability of rolling a 3 is 1/6.
Example:
You have a bag with 5 red marbles, 3 blue marbles, and 2 green marbles. What is the probability of picking a blue marble?
- Total possible outcomes: 10 (5 + 3 + 2)
- Favorable outcomes: 3 (blue marbles)
- Probability: 3/10
Key Terms:
- Outcome: A possible result of an event.
- Event: A specific outcome or set of outcomes.
- Favorable outcome: An outcome that you are interested in.
- Probability: The likelihood of a particular event happening.
Practice:
- What is the probability of rolling a 6 on a standard die?
- You have a deck of 52 playing cards. What is the probability of drawing a heart?
- A bag contains 10 balls, 4 of which are red. What is the probability of picking a red ball?
Remember:
Probability helps us make predictions and understand the likelihood of events. It's a valuable tool for making decisions in everyday life.