Analyzing One- and Two-Variable Data
Aligned to S-ID.B.6 — Common Core State Standards for Mathematics.
What this lesson teaches
When two variables are plotted as points on a scatter plot, a line of best fit is the straight line that comes closest to all the points, summarizing the trend. Its slope tells you how much one variable changes as the other increases by one.
Worked example
On a scatter plot of study hours versus test score, a line of best fit with slope 5 means each extra hour of study is linked to about 5 more points on the test.
Practice questions
- What does a line of best fit summarize?
- If a best-fit slope is 2, what does it mean per unit?
- Does a strong upward trend always prove one thing causes the other?
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
Análisis de datos de una y dos variables
Cuando dos variables se grafican como puntos en una gráfica de dispersión, la línea de mejor ajuste es la línea recta que más se acerca a todos los puntos, resumiendo la tendencia. Su pendiente te indica cuánto cambia una variable cuando la otra aumenta en una unidad.
Ejemplo: En una gráfica de dispersión de horas de estudio versus calificación en el examen, una línea de mejor ajuste con pendiente 5 significa que cada hora adicional de estudio se relaciona con aproximadamente 5 puntos más en el examen.
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