Addition Rule of Probability and Expected Frequency
Learn how to add probabilities for mutually exclusive events using P(A or B) = P(A) + P(B). Let’s get started! 🚀
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🛎️ What Are Equiprobable Events?
- Equiprobable events are events with the same chance of happening.
- When rolling a fair die, each number has an equal probability of 1/6.
🛎️ Calculating Probability: Single Event
- Probability equals number of favourable outcomes ÷ total outcomes.
- For example, drawing a blue ball from 50 balls with 25 blue gives 25/50 = 50%.
🛎️ Probability of “OR” Events
- Use OR when either event can happen.
- Add the favourable outcomes for each event, then divide by the total outcomes.
🛎️ Addition Rule for Probability
- Mutually exclusive events cannot happen at the same time.
- For example, a ball cannot be red and blue at the same time.
- When events are mutually exclusive, use P(A or B) = P(A) + P(B).
🛎️ Expected Absolute Frequency
- Expected absolute frequency is how often an event is expected to happen.
- It equals probability × number of trials.
- It is an estimate, so what actually happens can vary.
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Addition rule of probability
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