Stratified sampling
Lesson details
Learning outcome
I can carry out a stratified sample.
Key learning points
- A biased sample is not necessarily bad.
- You may wish to represent certain groupings in your sample.
- The sample from each group is proportional to the group size.
Keywords
Strata - A population may be split intro strata (groups). Each stratum is distinct and each item in the population can only belong to one stratum.
Stratified sample - A stratified sample is where a representative sample is taken from each stratum.
Common misconception
Stratified sampling is biased and therefore produces a bad sample.
Stratified sampling is used to take a representative sample from the population. Selecting from within the strata can be done using a simple random sample.
Teacher tip
Would it be fair to only survey one year group when considering food served in the school canteen? This question can be used to help pupils see that a representative sample may be biased but that intentional bias in a sample can be a good thing.
Licence
Lesson video
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Prior knowledge starter quiz
6 Questions
Q1.The population is the entire set of people, creatures, plants or items that make up the whole group which is being studied. A is a subset of the population.
Q2.A sample is when a member or group are more or less likely to be chosen for a sample compared to other members of the population.
Q3.Investigation: A scientist wants to check the biodiversity of plants and trees in Oak woods. What is the population in the scientist's investigation?
Q4.A teacher wants to select a simple random sample of six pupils from a class. Which of these can be used to generate a simple random sample?
Q5.These six pupils are assigned a range of numbers. A simple random sample of two pupils will be taken using these numbers. The range of integers that Jun should be assigned is .
Q6.These six pupils are assigned a range of numbers. A simple random sample of two pupils will be taken using these numbers. What calculation will generate a simple random sample for this population?
Assessment exit quiz
6 Questions
Q1.A teacher wants to split the students at his school based on the strata of the modern foreign language they are studying. Select the appropriate strata.
Q2.A population may be split into groups or strata. A sample is where a representative sample is taken from each stratum.
Q3.Select the sample that is most representative of the population from the given strata: A cruise ship with 2000 passengers and 500 crew.
A sample of 100 people is taken.
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 80 workers. How many workers from each band should be sampled?
Q5.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 under-16s for the sample.
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 over 65s for the sample.
To help you plan your 10 maths lesson on: Stratified sampling, download all teaching resources for free and adapt to suit your pupils' needs...
To help you plan your 10 maths lesson on: Stratified sampling, download all teaching resources for free and adapt to suit your pupils' needs.
The starter quiz will activate and check your pupils' prior knowledge, with versions available both with and without answers in PDF format.
We use learning cycles to break down learning into key concepts or ideas linked to the learning outcome. Each learning cycle features explanations with checks for understanding and practice tasks with feedback. All of this is found in our slide decks, ready for you to download and edit. The practice tasks are also available as printable worksheets and some lessons have additional materials with extra material you might need for teaching the lesson.
The assessment exit quiz will test your pupils' understanding of the key learning points.
Our video is a tool for planning, showing how other teachers might teach the lesson, offering helpful tips, modelled explanations and inspiration for your own delivery in the classroom. Plus, you can set it as homework or revision for pupils and keep their learning on track by sharing an online pupil version of this lesson.
Explore more key stage 4 maths lessons from the Sampling unit, dive into the full secondary maths curriculum, or learn more about lesson planning.