Sampling & populations

Greg and Hanna want to know if students at their school think lunchtime clubs are important.

Greg asks 15 people at the lunchtime chess club.

Give one reason why his results may not represent the whole school.

Here are Hanna’s results.

• 62% answered Important.

• 24% answered Not Important.

• The rest answered Don’t Know.

93 students answered Important.

How many students answered Don’t Know?

Rick claims most of the flats in his 8-floor building are energy efficient. He samples 45 flats from floors 1 to 5

Give a reason why this sample may not be useful in testing Rick’s claim.

Rick claims most of the flats in his 8-floor building are energy efficient. He samples 45 flats from floors 1 to 5

Give a reason why this sample may not be useful in testing Rick’s claim.

A survey was held in a football stadium. A sample of the crowd was asked about the importance of a family area. The pie chart represents the answers.

The total number of people in the crowd was 29 250 Estimate how many people in the crowd think that a family area is very important. Assume that the sample is representative of the crowd.

In fact, 50% of the sample were sitting in the family area 10% of the crowd were sitting in the family area. What is this likely to mean about the actual number of people in the crowd who think that a family area is very important? Tick one box.

Naga states a hypothesis. “Most people read more than 100 books a year.” She asks a sample of five people in a book club how many books they read last month. The table shows the results.

Show how Naga could use the data to support her hypothesis.

Give two reasons why this sample should not be used to support her hypothesis.

Kim works at an airport in the UK. She records the number of planes landing between 10 am and 2 pm each day. The table shows the data for the first 10 days in January.

The airport was affected by fog on one of the days. Which day do you think it was? Give a reason for your answer.

Kim uses the data to predict how many planes will land at the airport in a year. In her method, she uses an estimate of 150 planes in each 4-hour period throughout the day assumes the same number of planes each day. Work out her prediction.

In fact, fewer planes land in winter than in summer fewer planes land at night than during the day. What does this tell you about Kim’s prediction? Tick one box.

Give a reason for your answer.