Printable · GCSE Higher · ages 14-16

Sampling and inference about populations worksheet — GCSE Higher

Fifteen questions on "sampling and inference about populations" — DfE statement S1. Print it, or print three versions so neighbours cannot copy by letter; the key gives the letter for each version.

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Sampling and inference about populations worksheet — GCSE Higher

Maths · GCSE Higher · S1 · Sampling and inference about populations · 15 questions

MathsUKwww.geekhero.co.uk

1.A random sample of 50 pupils at a school were asked whether they prefer sport to music. 30 of the 50 pupils said they prefer sport. The school has 500 pupils altogether. Work out an estimate for the number of the 500 pupils who prefer sport.
(a)150 pupils
(b)200 pupils
(c)60 pupils
(d)300 pupils
2.A council wants to find out what all residents of a town think about a new cycle lane. It posts a survey only on its website and asks people to fill it in online. Give a reason why this sample is likely to be biased.
(a)People might lie on an online survey.
(b)The survey is free, so too many people will respond.
(c)Online surveys cannot stay anonymous.
(d)Only internet users reach the website; others are excluded.
3.A factory makes 4,000 light bulbs a day. In a random sample of 80 of one day's bulbs, 3 were faulty. Work out an estimate for the number of faulty bulbs the factory makes in a day.
(a)150 bulbs
(b)240 bulbs
(c)120 bulbs
(d)50 bulbs
4.A council in Leeds wants to know what local people think about letting shops stay open later in the evening. It rings landline telephone numbers between 10 am and 2 pm on a Tuesday. Write down which group is most likely to be under-represented in the sample, and give a reason for your answer.
(a)Children, as most of them are at home at that time
(b)Unemployed people, as most of them are out at that time
(c)Retired people, as most of them are at work then
(d)Full-time workers, as most are at work at that time
5.A town council wants to find out about the eating habits of the people who live in the town. It asks only the members of a local sports club. Give a reason why this sample is biased.
(a)The club has more members than the council needs
(b)The members were picked at random, so some will not reply
(c)Club members probably eat differently from most people
(d)Everyone asked lives in the town, so all are covered
6.A school has 1200 pupils. A teacher wants to take a random sample of 60 of them. Write down which of these methods gives a random sample.
(a)Drawing 60 names at random from a list of all 1200 pupils
(b)Asking the 60 pupils nearest the door at the first break
(c)Asking every pupil in two of the Year 10 classes
(d)Asking the 60 pupils who volunteer to take part
7.In a random sample of 40 pupils at a school, 6 are left-handed. The school has 900 pupils. Work out an estimate for the number of left-handed pupils in the school.
(a)6
(b)135
(c)22.5
(d)5400
8.A charity shop in Bath holds 2,000 books. Volunteer A checks a random sample of 50 books and finds 35 paperbacks. Volunteer B checks a different random sample of 50 books and finds 31 paperbacks. Work out the estimate each sample gives for the whole stock, and write down what the shop should do next.
(a)1,400 and 1,240, so combine the samples for one estimate
(b)1,400 and 1,240, so keep 1,400 as the larger estimate
(c)1,400 and 1,240, so one volunteer must have miscounted
(d)1,750 and 1,550, so the larger estimate must be right
9.A school has 1,500 pupils. The head teacher takes a random sample of 150 of them from the school register and asks how long they spend on homework. Rory says the sample is too small for the result to mean anything. Is Rory right? Give a reason for your answer.
(a)No, 150 pupils are a tenth of the school, chosen at random
(b)Yes, 150 pupils cannot be picked at random from 1,500
(c)No, a random sample always gives the exact school figure
(d)Yes, only asking all 1,500 pupils could show anything
10.A school has 1,000 pupils. A student wants to estimate how many of them walk to school, so she asks 8 pupils in her own class. She says her sample is large enough to give a reliable estimate for the whole school. Is she right? Give a reason for your answer.
(a)Yes — any sample size is equally reliable.
(b)No — because the sample was not taken online.
(c)No — 8 from one class is too small to represent the school.
(d)Yes — because 8 is more than half of her class.
11.A factory makes a batch of 4,000 circuit boards. It checks a random sample of 50 boards and finds that 4 are faulty. The factory will scrap the whole batch if the estimated number of faulty boards in the batch is more than 250. Should the factory scrap the batch?
(a)No — with an estimate of 80, below the 250 limit.
(b)No — only 4 faulty in the sample, far fewer than 250.
(c)Yes — with an estimate of 320, above the 250 limit.
(d)Yes — with an estimate of 500, above the 250 limit.
12.There are 10,000 pupils in a city. A researcher picks a sample of 500 of them by drawing names at random from a list of every pupil in the city. Give the reason why this method gives a representative sample.
(a)Because the pupils most willing to help are chosen
(b)Because the sample must be exactly 5% of the population
(c)Because every pupil has an equal chance of being picked
(d)Because 500 is large enough however they are chosen
13.A sports centre in Ipswich has 2,000 members. It wants to know what its members think of its opening hours, so it asks a random sample of 100 of them. Write down what the population is in this survey.
(a)Everybody who lives in Ipswich.
(b)All 2,000 members of the sports centre.
(c)The members who say they are unhappy with the opening hours.
(d)The 100 members who were asked.
14.A quality inspector weighs a random sample of 50 packets of crisps from one day's production and finds their mean mass is 32.4 g. The factory makes 20,000 packets that day. Work out an estimate for the total mass, in kg, of all the packets made that day.
(a)648,000 kg
(b)32.4 kg
(c)1.62 kg
(d)648 kg
15.A factory made 3,000 phone cases last week. Shift A checked a random sample of 100 cases and found that 34 were scratched. Shift B checked a different random sample of 50 cases and found that 21 were scratched. Using the COMBINED results from both shifts, work out an estimate for the number of scratched cases made last week.
(a)1140
(b)1020
(c)1260
(d)1100

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