Problem-Solving and Data AnalysisEasy–MediumScaling a sample proportion to a population
Problem-Solving and Data Analysis practice question
A random sample of 150 pupils at a school of 2,400 pupils finds that 45 walk to school. What is the best estimate of the number of pupils at the school who walk?
Answer: 720
45/150 = 0.3, and 0.3 × 2,400 = 720.
Common wrong answers
- If you answered 45
- 45 is the number in the sample.
- If you answered 72
- 72 is 0.3 × 240, a slip in the school's size.
- If you answered 800
- 800 uses a third instead of 45/150 = 0.3.
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