New
New
Year 10
•
Higher
Capture/recapture sampling method
I can use the capture/recapture sampling method to estimate population size.
New
New
Year 10
•
Higher
Capture/recapture sampling method
I can use the capture/recapture sampling method to estimate population size.
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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.
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.
Common misconception
Pupils may struggle to rearrange the equivalent fractions.
A ratio table may be easier for pupils to use instead.
Both equivalent fractions and ratio tables have been used throughout this lesson. You may prefer to use only one approach if you feel one approach is more suitable for your pupils.
Teacher tip
Licence
This content is © Oak National Academy Limited (2024), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).
Lesson video
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Starter quiz
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6 Questions
Q1.
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
Correct answer: Football
Football
Correct answer: Netball
Netball
Physics
Correct answer: Swimming
Swimming
Q2.
A may be split into groups or strata. A stratified sample is where a representative sample is taken from each stratum.
Correct Answer: population
population
Q3.
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
Correct answer: 180 patients and 20 staff
180 patients and 20 staff
170 patients and 30 staff
160 patients and 40 staff
Q4.
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
Correct answer: 50 band A, 70 band B and 40 band C
50 band A, 70 band B and 40 band C
Q5.
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.
Correct Answer: 203
203
Q6.
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.
Correct Answer: 192
192
Exit quiz
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6 Questions
Q1.
__________ is a sampling method which allows you to estimate the size of a population without counting it fully.
Capture
Correct answer: Capture-recapture
Capture-recapture
Random
Recapture
Stratified
Q2.
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.
Correct answer: Some hedgehogs may have chewed through the paper band.
Some hedgehogs may have chewed through the paper band.
Correct answer: Some hedgehogs may have lost the paper band when moving through hedges.
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.
Correct answer: Izzy’s sample size might have been too small.
Izzy’s sample size might have been too small.
Q3.
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?
Correct answer: Some of the birds may have died or migrated
Some of the birds may have died or migrated
Correct answer: More birds will have been born.
More birds will have been born.
Correct answer: More than one tree should be used.
More than one tree should be used.
Not enough time was left between the capture and the recapture.
The sample size was too large.
Q4.
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.
Correct answer: $$\frac{100}{x}=\frac{5}{50}$$
$$\frac{100}{x}=\frac{5}{50}$$
$$\frac{x}{100}=\frac{5}{50}$$
$$\frac{50}{100}=\frac{5}{x}$$
$$\frac{50}{100}=\frac{x}{5}$$
$$\frac{100}{x}=\frac{50}{5}$$
Q5.
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.
Correct Answer: 150, 150 deer
150, 150 deer
Q6.
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.
Correct Answer: 210, 210 squirrels
210, 210 squirrels