This video looks at a GCSE maths stratified sampling question and is aimed at around grade 5. The questions are fairly straightforward and, once you get used to the method, should be OK to solve:
Download a copy of the questions here: QT Stratified Sampling
Here’s a copy of the written answers: QT Stratified Sampling ANSWERS
1. The table shows the number of students in each year group at school.
| Year group | 7 | 8 | 9 | 10 | 11 |
| Number of students | 220 | 182 | 161 | 170 | 158 |
Joe is carrying out a survey and uses a stratified sample of 90 students.
Calculate the number of Year 9 students in Joe’s sample.
2. In a school 277 students each study one of three subjects.
| Maths | English | Science | |
| Male | 32 | 49 | 27 |
| Female | 41 | 56 | 72 |
A sample, stratified by language studied and by gender, of 60 of the 277 students is taken.
Calculate the number of female students studying English in the sample.
3. At a hospital 746 patients had the same operation. The table shows the age and gender of the patients.
| Aged under 18 | Aged 18 - 65 | Aged over 65 | |
| Male | 84 | 342 | 50 |
| Female | 39 | 194 | 37 |
The hospital wants to take a stratified sample of 80 patients. Complete the table to show how many people from each group should be sampled.
| Aged under 18 | Aged 18 - 65 | Aged over 65 | |
| Male | |||
| Female |
These types of questions appear in all the main GCSE exam boards – Edexcel, AQA, OCR and Educas.
Top Tips!
- Make sure you know the totals
- Try to work methodically and, preferably, down the page
- You don’t need to reduce the fraction, unless the question asks you to
Here’s a post that also might be of interest:
Stratified Sampling Questions; GCSE maths grade 5
Please do leave a comment below if you are not sure. Alternately you can view my YouTube channel and leave a comment there – I’ll always try to respond as quickly as possible.
Watch this video on YouTube:
Quick reminder – Stratified sampling GCSE maths