Surveys, Experiments, and Observational Studies
Aligned to S-IC.B.3 — Common Core State Standards for Mathematics.
What this lesson teaches
A sample survey questions a sample to describe a population; an observational study watches without intervening; an experiment imposes a treatment to test cause and effect. Randomization reduces bias, and in an experiment random assignment supports causal claims.
Worked example
To test a new fertilizer, an experiment randomly assigns plots to either fertilizer or none and compares yields. Because assignment is random, a difference in yield can be attributed to the fertilizer itself.
Practice questions
- Which type of study can establish cause and effect?
- Give an example of an observational study.
- Why is random assignment important in an experiment?
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
Encuestas, experimentos y estudios observacionales
Una encuesta por muestreo interroga a una muestra para describir una población; un estudio observacional observa sin intervenir; un experimento impone un tratamiento para probar causa y efecto. La aleatorización reduce el sesgo, y en un experimento la asignación aleatoria respalda las afirmaciones de causalidad.
Ejemplo: Para probar un fertilizante nuevo, un experimento asigna al azar parcelas a fertilizante o a ninguno y compara los rendimientos. Como la asignación es aleatoria, una diferencia en el rendimiento puede atribuirse al fertilizante mismo.
More Statistics & Probability lessons
Teach this lesson today
An AI tutor that guides with questions instead of just giving answers — all K–12 core subjects, every child in the family.
Start free — no card required