Events, Unions, and Complements
Aligned to S-CP.A.1 — Common Core State Standards for Mathematics.
What this lesson teaches
The sample space is the set of all possible outcomes, and an event is a subset of it. Combine events using union (A or B), intersection (A and B), and complement (not A).
Worked example
Roll a die, so the sample space is {1, 2, 3, 4, 5, 6}. Let A = even = {2, 4, 6} and B = greater than 3 = {4, 5, 6}. Then A and B = {4, 6}, A or B = {2, 4, 5, 6}, and the complement of A is {1, 3, 5}.
Practice questions
- List the sample space for flipping two coins.
- For a die roll, list the event "less than 3."
- If A = {1, 2, 3} on a die, list the complement of A.
Watch the lesson
Every lesson comes with a video taught in English and Spanish — the same video the QR code in the printed workbook opens.
▶ Watch this lessonEn español
Eventos, uniones y complementos
El espacio muestral es el conjunto de todos los resultados posibles, y un evento es un subconjunto de él. Combina eventos usando la unión (A o B), la intersección (A y B) y el complemento (no A).
Ejemplo: Lanza un dado, así que el espacio muestral es {1, 2, 3, 4, 5, 6}. Sea A = par = {2, 4, 6} y B = mayor que 3 = {4, 5, 6}. Entonces A y B = {4, 6}, A o B = {2, 4, 5, 6}, y el complemento de A es {1, 3, 5}.
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