Starter quiz
- A PE teacher wants to split the students at her school based on the strata of the sport the student enjoys the most. Select the appropriate strata.
- English
- Football ✓
- Netball ✓
- Physics
- Swimming ✓
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- A ______ may be split into groups or strata. A stratified sample is where a representative sample is taken from each stratum.
- 'population' ✓
- Select the sample that is most representative of the population from the given strata: A hospital with 1800 patients and 200 staff. A sample of 200 people is taken.
- 200 patients and 0 staff
- 190 patients and 10 staff
- 180 patients and 20 staff ✓
- 170 patients and 30 staff
- 160 patients and 40 staff
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- A company employs 250 band A workers, 350 band B workers and 200 Band C workers. A manager wants to take a stratified sample of 160 workers. How many workers from each band should be sampled?
- 40 band A, 70 band B and 50 band C
- 40 band A, 80 band B and 30 band C
- 50 band A, 60 band B and 50 band C
- 50 band A, 80 band B and 30 band C
- 50 band A, 70 band B and 40 band C ✓
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A bus company wants to take a sample of 1000 customers, stratified by age. The table shows the number of customers in each age group. The bus company should choose ______ under-16s for the sample.- '203' ✓
- A bus company wants to take a sample of 500 customers, stratified by age. The table shows the number of customers in each age group. The bus company should choose ______ 16-65 year olds for the sample.
- '192' ✓
Exit quiz
- __________ is a sampling method which allows you to estimate the size of a population without counting it fully.
- Capture
- Capture-recapture ✓
- Random
- Recapture
- Stratified
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- Izzy captures 10 hedgehogs and marks each one with a paper band around its leg. Izzy then recaptures 10 hedgehogs, but finds that none of them have a paper band. Select the possible reasons for this.
- Some hedgehogs may have chewed through the paper band. ✓
- Some hedgehogs may have lost the paper band when moving through hedges. ✓
- Izzy might have recaptured the same hedgehog twice.
- Izzy needed to wait longer before recapturing the hedgehogs.
- Izzy’s sample size might have been too small. ✓
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- To estimate the population of birds in a wood, 5 birds are captured from a single tree and marked. 9 months later, in a recapture of 10 birds, 0 were marked. Which factors may effect the results?
- Some of the birds may have died or migrated ✓
- More birds will have been born. ✓
- More than one tree should be used. ✓
- Not enough time was left between the capture and the recapture.
- The sample size was too large.
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- As part of a capture-recapture sample, 100 fish from a lake are captured and marked with a white dye. During a recapture of 50 fish, 5 were marked with the white dye. Select the correct statement.
- ✓
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- Andeep captures 15 deer and marks them by attaching a tag to their legs. Three days later, Andeep recaptures 30 deer, and 3 of them have a tag attached. Estimate the total number of deer.
- '150' ✓
- Jun captures 45 squirrels and marks them by attaching a tag to their legs. Three days later, Jun recaptures 70 squirrels, and 15 of them have a tag attached. Estimate the total number of squirrels.
- '210' ✓
Worksheet
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Presentation
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Video
Lesson Details
Key learning points
- There are situations in which you may not know the size of a population.
- The capture/recapture sampling method allows you to estimate population size.
- The size of the initial sample affects how accurate your estimation will be.
Common misconception
Pupils may struggle to rearrange the equivalent fractions.
A ratio table may be easier for pupils to use instead.
Keywords
Capture/recapture - Capture-recapture is a sampling method which allows us to estimate the size of a population without counting it fully. It is very useful when the entire population may be too difficult to count.
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