The Statistical Enquiry Cycle is a cycle used to carry out a statistical investigation. There are five stages. This is an ongoing process as evaluation may lead to new/refined questioning.

The Statistical Enquiry Cycle

Maths

Checking understanding of statistical problems

Types of data

Sampling methods

Stratified sampling

Capture/recapture sampling method

Sampling limitations

Data collection

Biased questioning

Advanced problem solving with sampling

In this unit, pupils are given the opportunity to assess how valid a sample may be and what the averages might tell us. In the future unit, pupils extend their knowledge of averages to stem and leaf diagrams as well as comparing two data sets.

In the prior unit, pupils considered the mean, median and mode and evaluated their usefulness in a variety of contexts. In this unit, pupils are given the opportunity to consider where the data came from and how it was collected and can therefore start to evaluate how good a representation the sample is of the whole population.

In this unit pupils will learn how to sample, and explore accuracy and limitations with various sampling strategies and data collection techniques.

Sampling

Put the stages of the Statistical Enquiry Cycle in order. Start with the stage that should come first when you first begin a statistical enquiry.

Sofia is conducting a survey to find out how often people visit the gym. Which stage of the Statistical Enquiry Cycle does this event fit in?

Deciding to research the safety of driverless cars

Looking at results and deciding what they show

Match each stage of the Statistical Enquiry Cycle to an event.

Which stage is missing from this Statistical Enquiry Cycle?

Jun wants to know what options the year 9 pupils in his school might choose for GCSE. He plans to ask 'What subject is your favourite?'. What statistics can he find with the data from this question?

Laura wants to find out whether pupils who are good at throwing the javelin are also good at shotput. She collects data for 20 pupils on best javelin and shotput throws. What chart should Laura use?

Data has been collected and processed about the number of sweets per packet in 3 different multipacks. The company claims ‘an average of 15 sweets per pack’. Which multipack best supports the claim?

Izzy’s variety of scores is lower than Jun’s.

Izzy’s middle score was lower than Jun’s.

Izzy’s average, typical score is lower than Jun’s.

Izzy's most common maths score is lower than Jun's

Izzy and Jun compare their scores in their last 10 maths tests. The tables show the summary statistics. Select the statements that are correct about the **mode** of their scores.

Izzy’s variety of scores is greater than Jun’s.

Izzy's test results are more consistent than Jun's.

Izzy's test results are less consistent than Jun's.

Izzy and Jun compare their scores in their last 10 maths tests. The tables show the summary statistics. Select the statements that are correct about the **range** of their scores.

Yes, the sample is representative of all adults.

No, Jacob's sample is biased as people in the gym are more likely to exercise.

No, Jacob needs to survey more people from the gym to be sure.

No, Jacob needs to survey people from the gym on different days to be sure.

Jacob went to the gym and surveyed 10 adults in the gym to find out how much exercise they do a week. The mean was 5 hours. Jacob says, "All adults exercise for 5 hours a week." Is he correct?

There is less variability in the number of frosty days in Bristol.

Bristol is likely to be warmer in December than York as the mean is lower.

York has fewer frosty days than Bristol as the range is lower.

Bristol is likely to be colder in December than York as the range is higher.

There is less variability in the number of frosty days in York.

The table of summary statistics shows the number of days of air frost each day in December over the last 10 years. Select the correct statements.

Starter Quiz

Select all the measures of spread.