Research Methods: Sampling Techniques - KU Flashcards
A group of people who are the focus of the researcher are called?
Target Population
Define Target Population
The group of people the researcher is interested in
What is a sample?
A group of people taken from the target population to take part in the research
What is the name for the group of people who are taken from the target population to take part in the research?
Sample
Name the sampling technique whereby every person has an equal chance of people selected
Random Sampling
What is random sampling?
Every person in the target population has an equal chance of being selected
Complete the missing steps for how to carry out random sampling
- Create a complete list of all the target population
- Without looking select the number you want in your sample from the hat
- Write the names on equal size pieces of paper and put in a hat
Why is random sampling time consuming?
This is because it takes time and can be difficult collecting all the names of the ppts to take part in the study & people may not be willing to take part.
Which 2 sampling methods are the most time consuming?
Random sampling
Stratified sampling
Define systematic sampling
A ‘system’ that is applied to select ppts
e.g. selecting every 4th or 8th person until there are enough ppts for your sample
What sampling method is it?
Systematic sampling
How does systematic sampling avoid researcher bias?
The researcher has no influence over who is chosen to take part in the study - as it is objective once the system to select ppts is established
If the researcher has no influence over who is chosen to take part in the study, and it is an objective way to select ppts - what does this sampling method NOT suffer from?
Researcher Bias
Identify one problem with systematic sampling
Might not be representative
Why might systematic sampling not be representative?
Not everyone has an equal chance of being picked therefore it is difficult to generalise the findings to the target population
Why might systematic sampling be time consuming?
Creating a system and collecting names could be time consuming and difficult for the researcher
What is meant by stratified sampling
An advanced way of sampling where the make-up of the sample reflects the proportions of certain sub-groups in the target population
e.g. 70% of the target population is male then 70% of the sample will be female too
What sampling method is this?
Stratified sampling
Complete the missing step:
- Identify the sub groups that make up a population e.g. males and females
- Calculate how many of each proportion you would need for your sample
3.
- No. of ppts which make up each proportion are chosen using random sampling
If the scenario does give you % - what is the formula for stratified sampling
sample size wanted/100 x percentage size of sub group
Why is stratified the most representative?
It accurately reflects the make-up of the target population in the correct proportions, meaning the findings can be generalised
Why is it more appropriate to generalise the findings for stratified sampling?
Stratified sampling accurately reflects the make-up of the target population in the correct proportions
Why is stratified sampling so time consuming?
It takes time to work out the proportions of the PPTs needed and it is not guaranteed PPTs would consent to take part
What is meant by opportunity sampling?
Selecting participants that are there at the moment in time - for example waiting for PTTs in the canteen during period 3 and asking the first 30 PPTs who walk past to participate
How might you carry out opportunity sampling?
Go somewhere where you will have access to the population you want to study and ask the first 30 PPTs who are there at the moment in time if they will take part
Why might opportunity sampling be less time consuming than random sampling?
Opportunity sampling is less time consuming as less money is required because you choose who is available at the time for your sample, unlike random sampling which takes a long time to identify everyone in the target population
Explain why opportunity sampling might not be the most representative of the target population
PPTs picked from the sample are present in the same place at the same time, doing similar things therefore might have similar personalities - making it difficult to generalise findings to the wider population
Define self selected
Where PPTs volunteer themselves to be participants in a research study
What is meant by volunteer sampling?
It is a self selected method where people volunteer themselves to be PPTs
How do you obtain PPTs from volunteer sampling?
Place an advert where people in the target population will see it and wait for the first 30 people to reply
What sampling method requires people to respond to an advert?
Volunteer sample
What is a strength of volunteer sampling?
Very quick, easy and cheap to conduct as all you do is place and advert and wait for your PPTs to volunteer
Why might volunteer sampling be more appropriate than random sampling?
Volunteer sampling is quick, easy and cheap to carry out as all you do is place an advert for the study where the target population will be unlike random sampling which takes time to place names in a hat and give the population an equal chance of being picked
Explain why volunteer sampling might not be representative?
Only certain personality types will volunteer (extrovert/curious) making it difficult to generalise the findings to the target population
