Drawing Inferences from Samples
Aligned to 7.SP.A.2 — Common Core State Standards for Mathematics.
What this lesson teaches
You can use a random sample to estimate a feature of the whole population by scaling the sample proportion up. Because different samples vary, these estimates are approximate, not exact.
Worked example
In a random sample of 50 voters, 30 favor a measure. That is 30/50 = 0.6. For a town of 4,000 voters, estimate 0.6 × 4,000 = 2,400 in favor.
Practice questions
- In a sample of 40 fish, 6 are tagged. Estimate the fraction of the lake that is tagged.
- A random sample of 200 light bulbs has 8 defective. Estimate the number of defects in 5,000 bulbs.
- Why might two different random samples give slightly different estimates?
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
Sacar Inferencias a partir de Muestras
Puedes usar una muestra aleatoria para estimar una característica de toda la población ampliando la proporción de la muestra. Como las muestras varían, estas estimaciones son aproximadas, no exactas.
Ejemplo: En una muestra aleatoria de 50 votantes, 30 apoyan una medida. Eso es 30/50 = 0.6. Para un pueblo de 4,000 votantes, estima 0.6 × 4,000 = 2,400 a favor.
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