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Glossary
Look up any term from this course. Each entry links back to the lesson that taught it.
| Term | Definition | Lesson |
|---|---|---|
| Complementary events | An event and "not" that event — their probabilities always add up to . | Complementary Events |
| Expected frequency | A prediction of how many times an event will occur: probability × number of trials. | Expected Frequency |
| Experimental probability | An estimate of probability from real data: (times the event happened) ÷ (total trials). Also called relative frequency. | Probability From Data |
| Independent events | Two events where one's outcome does not affect the other's probability — for these, P(A and B) = P(A) × P(B). | Combined Events: AND |
| Mutually exclusive events | Two events that cannot both happen at the same time — for these, P(A or B) = P(A) + P(B). | Combined Events: OR |
| Probability | A number from (impossible) to (certain) measuring how likely an event is. | Introduction to Probability |
| Sample space | The complete set of all possible outcomes of an experiment. | Introduction to Probability |
| Tree diagram | A diagram showing every possible outcome of a sequence of events, with probabilities multiplied along a path and added across matching paths. | Tree Diagrams |
More lessons in Basic Probability · Previous: Course Exam