Center, Spread, and Shape
Aligned to 6.SP.A.2 — Common Core State Standards for Mathematics.

What this lesson teaches
A data set is described three ways: its center (a typical value like the mean or median), its spread (how far the values stretch), and its shape (are values bunched, even, or skewed?).
Worked examples
Example 1
For test scores 80, 82, 85, 88, 90: the center (median) is 85, the spread (range) is 90 − 80 = 10, and the shape is fairly even with no big gaps.
Example 2
For 10, 12, 12, 13, 40: the median is 12 and the range is 30, but that 40 is an outlier stretching the spread far past where most values sit.
Example 3
Shape matters. Scores clustered at the top with a long tail down look very different from scores spread evenly, even with the same mean.
Practice questions
- Find the median (center) of 4, 7, 9, 12, 15.
- Find the range (spread) of 20, 22, 30, 45.
- Describe the shape of a data set where most values cluster low with one very high value.
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
Centro, Dispersión y Forma
Un conjunto de datos se describe de tres maneras: su centro (un valor típico como la media o la mediana), su dispersión (qué tanto se extienden los valores) y su forma (¿están agrupados, parejos o sesgados?).
Ejemplo 1: Para las calificaciones 80, 82, 85, 88, 90: el centro (mediana) es 85, la dispersión (rango) es 90 − 80 = 10, y la forma es bastante pareja sin grandes huecos.
Ejemplo 2: Para 10, 12, 12, 13, 40: la mediana es 12 y el rango es 30, pero ese 40 es un valor atípico que estira la dispersión mucho más allá de donde está la mayoría.
Ejemplo 3: La forma importa. Calificaciones agrupadas arriba con una cola larga hacia abajo se ven muy distintas de calificaciones parejas, aun con la misma media.
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