Learn about probability and how it applies in real world. Grade 9 Alberta mathematics curriculum.
Lesson 9.1 of Probability & Statistics in Grade 9 Math: Alberta curriculum lessons.
Probability is the study of how likely an event is to happen. It helps us make predictions about uncertain situations, like whether it will rain tomorrow or if a coin will land on heads.We use probability to describe the chance of something occurring. It's usually written as a fraction, decimal, or percent between 0 and 1: 0 → the event is impossible (it can't happen); 1 → the event is certain (it will definitely happen); Anything in between → the event is possible, but not guaranteed
Theoretical probability is what should happen in theory, based on mathematical reasoning.
Example:
When you roll a fair 6-sided die, the chance of getting a 3 is:
Experimental probability is based on actual results from experiments, what really happens, not just what should happen.
Example:
If you roll a die 60 times and get a "3" 8 times, then:
Probability isn't just about dice, coins, or cards. It's something we use in everyday decisions. We often think about how likely something is to happen, even if we don't write it as a fraction or percent.
For example:.
These are all decisions based on probability, even when we make them instinctively.
Sometimes, we make judgments based on personal beliefs or experiences, not exact data. This is called subjective probability. It's based on what we feel is likely, rather than what the numbers say.
People often make decisions using assumptions, ideas they accept as true without checking all the facts.
If a basketball player makes 3 out of every 5 shots on average, the theoretical probability of making a basket is 3/5 = 0.6.If, in a game, the player takes 10 shots and makes 4, the experimental probability is 4/10 = 0.4. Over time, with more data, the two values will likely become closer.
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