Problem-Solving and Data AnalysisEasy–MediumEstimating a population count from a sample
Problem-Solving and Data Analysis practice question
In a random sample of 300 households in a town of 8,000 households, 90 have a dog. What is the best estimate of the number of households in the town that have a dog?
Answer: 2400
The sample proportion is 90/300 = 0.3, so about 0.3 × 8,000 = 2,400 households.
Common wrong answers
- If you answered 90
- 90 is the number in the SAMPLE.
- If you answered 240
- 240 is 0.3 × 800, a slip in the town's size.
- If you answered 2667
- 2,667 uses 8,000/3, dividing instead of multiplying by the proportion.
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