🤔 Will It Happen?
Probability is the study of how likely something is to happen. From weather forecasts to games, probability helps us understand and predict the world around us.
📏 The Probability Scale
Probability ranges from 0 to 1
0 (Impossible)
0.5 (Even chance)
1 (Certain)
❌
Impossible (0)
Rolling a 7 on a normal dice
🤷
Unlikely
Rolling a 6
⚖️
Even (0.5)
Flipping heads
👍
Likely
Not rolling a 1
✅
Certain (1)
Sun rising tomorrow
🧮 Calculating Probability
The Formula
P(event) = Favourable outcomes / Total possible outcomes
Example: Rolling a 3
On a normal dice:
- Favourable outcomes = 1 (just the 3)
- Total outcomes = 6 (1, 2, 3, 4, 5, 6)
- P(3) = 1/6 ≈ 0.17 or about 17%
📖 Probability Language
Words We Use
- Impossible — cannot happen (0%)
- Unlikely — probably won't happen
- Even chance — 50/50
- Likely — probably will happen
- Certain — will definitely happen (100%)
📊 Types of Probability
Theoretical vs Experimental
- Theoretical — what SHOULD happen mathematically
- Experimental — what ACTUALLY happens when you try it
The more trials you do, the closer experimental gets to theoretical!
✏️ Activities
Activity: Coin Flip Experiment
- Flip a coin 20 times
- Record heads: _____ Tails: _____
- What is your experimental probability of heads?
- How does it compare to the theoretical (0.5)?
Calculate These
A bag has 3 red, 2 blue, and 5 green marbles:
- P(red) = ___
- P(blue) = ___
- P(not green) = ___
My calculations:
👩🏫 Teacher Notes
Curriculum Links
- Mathematics: Statistics — probability