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A school in Brisbane wants to estimate the average number of hours Year 8 students spend on homework each week. The school has 420 students in Year 8.
A random sample of 30 students is selected, and the total hours reported by the sample sum to 450 hours.
What is the exact average number of hours per student in the sample?
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Worked solution
- The problem states that a random sample of 30 Year 8 students from a school in Brisbane was surveyed. The total number of hours spent on homework by these 30 students is 450 hours. We are asked to find the average number of hours per student in the sample.
- To find the average, we use the formula: average = total sum of values ÷ number of values. Here, the total sum is 450 hours, and the number of students is 30.
- Substitute the values into the formula: average = 450 ÷ 30. Perform the division: 450 ÷ 30 = 15.
- The result is 15 hours. The units are hours per student, which is appropriate for the average time spent on homework.
- Check: 30 students × 15 hours = 450 hours, which matches the given total. The calculation is correct.
Reference answer: 15 hours
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