If you want to check that your calculations are correct, then add up the totals for each group and the total should be the desired total of 200. Calculate how many people she will need to sample from each age group. Since 120 out of the 192 students are boys, we can write this as a fraction, and simplify: If \frac{5}{8} of the year group are boys, this means that \frac{5}{8} of the 16 year 9 students he plans to survey have to be boys. Practice Questions; Post navigation. Sampling Methods www.naikermaths.com Sampling Methods - Edexcel Past Exam Questions MARK SCHEME 1. Michael is conducting a stratified sample of sports players at his university. Doing so, we get that the number of people to be sampled from each group (in order) is. Adding up the numbers, we get, \text{total population }=132+678+543+289+108=1,750, Step 2: We must apply the formula shown above. The number she should sample from the 5 – 15 group is. Stratified sampling is a method we can use to make our sample more representative. Primary Study Cards. Please reload CAPTCHA. There are 500 people at her company. Log in. The table below outlines the population of her village separated by their incomes: Calculate the number of people she should sample from each income range. Question 3: A University has 3 sports clubs: a football club, a rugby club, and a basketball club. We have a range of learning resources to compliment our website content perfectly. We'll assume you're ok with this, but you can opt-out if you wish. Complete the table. Next Random Sampling Answers. The 41 – 60 group: \dfrac{\textcolor{blue}{289}}{\textcolor{limegreen}{1,750}}\times 80=13.211... Lastly, the 61+ group: \dfrac{\textcolor{blue}{108}}{\textcolor{limegreen}{1,750}}\times 80=4.937... Obviously, we can’t select decimal numbers of people, so we have to round all these values to the nearest whole number. Therefore, the head of maths needs to survey 10 year 9 boys. Make sure you are happy with the following topics before continuing. Question 2: A house leader is doing a student voice survey about the sports facilities at her school. %��������� Time limit is exhausted. By separating the population into groups (age groups, genders, etc.) By clicking continue and using our website you are consenting to our use of cookies in accordance with our Cookie Policy, 20% off all revision materials - enter code mme20 at checkout, Not sure what you're looking for? (a) Describe how a stratified sample of 200 staff could be taken. Click here for Answers . Step 1: First, we need to establish how many people were at the convention. We never share your details. The breakdown of ages of all visitors to a convention is given in the table below. Revise. For each year group, the number of students to be surveyed per year group can be calculated as follows: Year 7: \dfrac{112}{6}=19\text{ students}, Year 8: \dfrac{104}{6}=17\text{ students}, Year 10: \dfrac{90}{6}=15\text{ students}, Year 11: \dfrac{76}{6}=13\text{ students}. Therefore, if there are 270 students in the sixth form, of which 156 are in year 12, then we can easily work out the number of students in year 13: Question 5: The head of maths wants to take a survey to obtain information about the quality of the teaching that the students in the school are receiving. View all Products, Not sure what you're looking for? How to use a probability tree diagram – GCSE mathematics, How to work with indices – GCSE maths practice questions, How To Work Out Reverse Percentages – GCSE mathematics, Histograms – GCSE Mathematics questions and answers. 5-a-day Workbooks. Worksheets & Exam Questions. Given that there are 255 females at the company and 51 in the sample, we get. stream Question 1: Ana wants to conduct a survey on the eating habits of people in her village. The Corbettmaths Textbook Exercise on Stratified Sampling. The main things to remember when working with GCSE mathematics stratified sampling questions are: Check that you know the total population size – this is sometimes given, although it’s always good to confirm; A fraction can be read as ‘out of’ so 42/85 means 42 out of 85. GCSE Revision Cards. Odette has taken a stratified sample of people who work at her company based on gender. The 10 most common maths exam mistakes ... and how to avoid them. This sampling method is also called “random quota sampling". GCSE Mathematics Proof Questions – Answers, GCSE Mathematics Vector Questions – Answers, Highest Common Factor HCF & Lowest Common Multiple LCM, Check that you know the total population size – this is sometimes given, although it’s always good to confirm. Stratified Sampling Questions, Worksheets and Revision Level 6-7 . Since the rugby club has a total of 91 members, the number included in the sample can be calculated as follows: For the basketball team, we have been given the sample size and not the total number of members in the club. Stratified Sampling. We have been given complete information for the football club, and we can see that there are 196 players in total, of which 28 have been selected for the sample. Try a Revision Card. We know that there is a total of 192 students in year 9, so the total number of students he needs to survey in year 9 can be calculated as follows: However, the head of maths can’t simply survey 8 boys and 8 girls because he is also stratifying by gender as well as age. Anti spam - please answer to leave a comment. Previous topic Next topic. So, instead of using the formula, we’re going to consider the fact stated just above: “the ratio of the groups in the sample must equal the ratio of the groups in the population”. \text{Total population }=1,354+3,480+3,776+1,865+430=10,905.