Sampling Flashcards
What is meant by the term population?
A group of people who are the focus of the researcher’s interest, from which a smaller sample is drawn.
Why is it usually not possible to include all members of the population in a study?
Due to practical and economic factors such as time and money.
What is a sampling technique?
A method used to select participants from the population.
What is meant by the term generalisation?
The extent to which findings and conclusions from a particular investigation can be broadly applied to the population.
What is random sampling?
All members of the population have an equal chance of being chosen.
- All population members are numbered then through a lottery method, a sample of random numbers is chosen (which correspond to members of the population).
What is the target-population?
A subset of the general population that is more specific.
Random sampling makes use of lottery methods, what are these?
A computer-based randomise or picking numbers from a hat.
In which sample does every member of the population have an equal opportunity for being selected?
Random sampling.
What is meant by the term sample?
The group of people selected who take part in the research, they are drawn from the (target) population and is presumed to be representative of the whole population.
The vast majority of samples contain some type of bias, what is meant by the term bias?
When certain groups may be over or under-represented in the sample.
Why do we assume that the sample is representative of the target population?
So that we can generalise our results to a wider audience.
Why does bias in the sample limit the ability to generalise results?
Because when there is bias in the sample, it is no longer representative of the population and cannot be generalised.
From where is a sample taken?
From the (target) population.
Explain the process of taking a random sample:
1) A complete list of all target population members is acquired.
2) Every member is numbered.
3) The sample of numbers is generated through some lottery method.
(Each number corresponds to a member of the pop.)
List the main sampling techniques used to generate a sample from a population:
- Random sampling,
- Systematic sampling,
- Stratified sampling,
- Opportunity sampling,
- Volunteer sampling.
Which sampling type uses the mathematical ‘nth’ term sequence?
Systematic sampling.
What makes generalisation possible?
Generalisation is made possible by the sample being representative of the population.
How do you generate a sampling frame for systematic sampling?
Make a list of every member of the target population ordered by some factor, e.g. alphabetically.
What is an opportunity sample?
Where the researcher simply takes anyone who is available and accessible at the time.
Which type of sampling technique would generate a mathematical sequence?
Systematic sampling.
Which technique has been referred to as a ‘self-selection’ process?
Volunteer sampling.
Explain how a researcher may carry out a volunteer sample?
They may place an advert in a newspaper or a poster and wait for participants to come forwards.
Which sampling technique may involve walking into the street and taking anyone who is down to do the study?
Opportunity.
A sampling frame is required for which type of sampling?
Systematic.
Which sampling method is the only one which the researcher doesn’t “select” participants themselves?
Volunteer sample.
Which forms of sampling are considered the most sophisticated?
Random sampling and Stratified sampling.
What is the aim of stratified sampling?
To obtain a sample in which the sample reflects the proportions of people in certain sub-groups (stratas) within the (target) population.
What can be done to a systematic sample to try and increase the randomness?
The sampling system (‘nth number’) can be decided through a random number generator.
Which sampling technique may involve waiting outside a supermarket and stopping every 10th person who comes in?
Systematic sample.
Explain how to carry out a systematic sample:
- Create a sampling frame by organising every member of the target population into a list.
- Nominate a sampling system (e.g. every 8th person).
- Work through the sampling frame until sample is complete.
What are stratas?
They are sub-groups of a wider population used in stratified sampling.
AO3 - Advantages of volunteer sampling.
- Requires little effort from the researcher and easy to get a sample.
Which sampling technique involves generating a strata?
Stratified sampling.
AO3 - Advantages of random sampling.
- Unbiased because every member of the population has an equal chance of being chosen.
AO3 - Disadvantages of random sampling.
- Can be very time-consuming to number and generate is target population is large.
- Sample may still be unrepresentative due to the random nature.
AO3 - Disadvantages of volunteer sampling.
- Tends to attract a certain type of person (people-pleasers).
AO3 - Advantages of opportunity sampling.
- Very easy and accessible to gain participants.
AO3 - Disadvantages of opportunity sampling.
- Not representative as only specific places or areas.
AO3 - Advantages of systematic sampling.
- Avoids any forms of researcher bias.
AO3 - Disadvantages of systematic sampling.
- Can easily be unrepresentative of the population.
AO3 - Advantages of stratified sampling.
- Highly representative of the population.
AO3 - Advantages of stratified sampling.
- Highly representative of the population.
- Also no researcher bias as ptps are randomly selected.
AO3 - Disadvantage for all sampling techniques.
Selected participants may also refuse to take part, which means it turn more into a volunteer sample.
A disadvantage of volunteer sampling is that it may attract a certain type of person, what type of person is this?
Someone who is helpful, keen and curious.
