Consolidation Exercise 1 Learning Objectives To consolidate on

Consolidation Exercise 1 • Learning Objectives: To consolidate on exam questions linked to chapter 1 • Starter: What are the different types of sampling and explain one of them?

Sampling • The Population is all the people or objects you are interested in. • When it is too costly or difficult to include the whole population, a sample is used instead. The sample needs to give a good indication of what results would be like from the whole population. Otherwise it is a biased sample. The bigger the sample the better. 20 is the minimum number to be used.

Types of sampling • • • Random sampling Cluster sampling Systematic sampling Stratified sampling Quota sampling

Random Sampling • A random sample is a sample taken in such a way that every member of the population has an equal chance of being included. Random sampling methods include: • drawing ‘names’ ‘out of a hat’ • Numbering all members of the population, then using random numbers from the calculator to select the sample

Cluster Sampling • This is where the population is split into smaller groups called clusters. One or more clusters are chosen at random. The sample is everyone in those clusters. • What are the pros and cons? • It is easy to do but it can be biased if the clusters are different.

Systematic Sampling • This is where you pick a starting point at random then choose the rest of the sample at regular intervals. • Example if you have 30 names and needs to pick 10 names. 30 divided by 10 = 3. • You choose a starting point say number 2 on the list and then choose every 3 rd member after that. It could be biased because of the order of the list.

Stratifed Sampling • A Stratifed sample is divided into groups or strata. See example 1 on page 11 of the text book.

Quota Sampling • The people in the sample just have to be of a particular type. This is often used by market researchers doing interview in the street. They might be told to look for: • 20 women with young children • 30 business men • 50 teenagers. As long as people meet these criteria it is up to the interviewer who to ask. • It could be biased.

• A representative sample is a sample chosen to reflect the number in each subgroup of the population where the subgroups are defined by characteristics which may include gender, age or other relevant features

• Students to complete Page 42, questions 1 and 2.

• Plenary: Peer assessment