Sampling - Research Methods [A-Level Psychology]
Summary
TLDRThis video explores various sampling techniques in psychological research, including Random, Systematic, Stratified, Opportunity, and Volunteer sampling. It discusses the importance of representative samples for generalizing findings to the wider population and the potential biases associated with each method. The video also addresses WEIRD participant bias and its implications for the global applicability of psychological research.
Takeaways
- 🔍 The video discusses the importance of sampling in psychological research and the need to consider whether findings can be generalized to the wider population.
- 🎯 The target population is defined as every individual that forms part of the group being studied, and researchers aim to generalize results from samples back to this population.
- 📈 Five sampling techniques are introduced: Random, Systematic, Stratified, Opportunity, and Volunteer, each with its own strengths and weaknesses.
- 🎰 Random sampling ensures every member of the population has an equal chance of being selected, which helps to avoid researcher bias.
- 🔢 Systematic sampling involves selecting members at regular intervals from a list, which is quick but can still potentially lead to unrepresentative samples.
- 👥 Opportunity sampling is the most accessible method, using readily available participants, but it is prone to researcher bias and may not be representative.
- 🙋 Volunteer sampling, where participants self-select, can reach a large audience but suffers from volunteer bias, as it may not include a diverse range of individuals.
- 🏛 Stratified sampling is the most complex and aims to create a sample that mirrors the population's subgroups, which helps in generalizing findings accurately.
- 🌐 The concept of 'WEIRD' participants (Western, Educated, Industrial, Rich, and Democratic) is highlighted as a potential bias in psychological studies, questioning the global applicability of research findings.
- 👩🏫 Historical studies are criticized for often ignoring or underrepresenting women, leading to considerations of gender bias in psychological theories.
- 📚 The video concludes by promoting tutorial videos and resources for further study on research methods in psychology.
Q & A
What is the importance of sampling in psychological research?
-Sampling is crucial in psychological research because it allows researchers to study a subset of a larger population, which is often impractical to test in its entirety. The goal is to obtain a sample that is representative of the population to ensure that the findings can be generalized.
What are the five sampling techniques discussed in the video?
-The video discusses five sampling techniques: Random, Systematic, Stratified, Opportunity, and Volunteer sampling.
How does random sampling work and what are its strengths and weaknesses?
-Random sampling involves selecting participants from a population such that each member has an equal chance of being chosen. This method avoids researcher bias but can sometimes result in an unrepresentative sample, especially if the population is large.
What is systematic sampling and how does it differ from random sampling?
-Systematic sampling involves selecting members from a list at a regular interval, such as every 5th or 10th person. It is similar to random sampling but differs in the selection process, which is more structured. It also removes researcher bias but can be prone to the same issues of unrepresentativeness as random sampling.
Why is opportunity sampling a common method in psychological studies?
-Opportunity sampling is common because it is the easiest and fastest way to obtain a sample. Researchers simply include anyone they can easily access, often leading to studies being conducted on university students. However, it can introduce researcher bias and may not be representative of the wider population.
What is a volunteer sample and what are the potential biases associated with it?
-A volunteer sample, also known as a self-selecting sample, consists of individuals who choose to participate in a study. While it can reach a large number of participants, it introduces volunteer bias because those who volunteer may not represent the wider population, often being more motivated or having more time to participate.
How does stratified sampling aim to overcome the limitations of other sampling methods?
-Stratified sampling creates a sample that is representative of the population by first identifying subgroups (strata) and their proportion in the population. Participants are then randomly selected from each strata to ensure the sample mirrors the population's composition. This method reduces bias and increases the confidence in generalizing the findings.
What is the criticism of psychology studies regarding the term 'WEIRD' participants?
-The term 'WEIRD' refers to the fact that many psychology studies have been conducted on participants from Western, educated, industrial, rich, and democratic backgrounds. This leads to questions about the applicability and generalizability of psychological findings to diverse populations worldwide.
What is the role of generalization in psychological research?
-Generalization in psychological research refers to the ability to apply the findings from a sample back to the target population. It is a critical aspect of research as it allows researchers to make broader claims about the population based on the study's results.
How does the video script address the issue of gender bias in historical psychological studies?
-The script mentions that historical studies often ignored or underrepresented women, leading to potential gender bias in accepted psychological theories. This highlights the importance of considering diverse samples in research to avoid such biases.
Outlines
🔍 Introduction to Sampling Techniques in Psychology Research
This paragraph introduces the concept of sampling in psychological research, emphasizing the importance of selecting a representative sample to ensure that study findings can be generalized to the broader population. The paragraph outlines five sampling techniques: Random, Systematic, Stratified, Opportunity, and Volunteer. It also highlights the need to consider the strengths and weaknesses of each method. The target population is defined as the entire group that a researcher plans to study, and the goal is to select a sample that accurately represents this population. The concept of generalization, where results from a sample are applied back to the target population, is discussed, along with the challenges of achieving representativeness due to the variability within populations.
📊 Exploring Different Sampling Techniques and Their Implications
This paragraph delves into the specifics of each sampling technique, discussing how they work and their respective advantages and disadvantages. Random sampling is described as a method that gives every individual in the population an equal chance of being selected, which helps to avoid researcher bias but may sometimes result in an unrepresentative sample. Systematic sampling involves selecting members at regular intervals from a list, which is efficient but can also lead to unrepresentative samples if not carefully managed. Opportunity sampling is the most accessible method, where researchers include whoever is available, which is fast but prone to researcher bias and often not representative. Volunteer sampling, where participants self-select, can reach a large audience but suffers from volunteer bias, as those who volunteer may not be representative of the wider population. Stratified sampling is the most complex method, aiming to create a sample that mirrors the population's subgroups, which helps in generalizing findings but can be time-consuming and may introduce bias in the selection of strata.
Mindmap
Keywords
💡Sampling
💡Target Population
💡Generalisation
💡Random Sampling
💡Systematic Sampling
💡Opportunity Sampling
💡Volunteer Sampling
💡Stratified Sampling
💡Bias
💡WEIRD Participants
Highlights
The importance of considering who participates in a study and if their behavior can be generalized to everyone.
Introduction to five sampling techniques: Random, Systematic, Stratified, Opportunity, and Volunteer.
Definition of the target population and the concept of generalization from a sample back to the population.
The process and benefits of random sampling to avoid researcher bias.
Challenges with random sampling, such as the potential for unrepresentative samples and time-consuming nature with large populations.
Systematic sampling method and its similarity to random sampling with a fixed interval selection.
Advantages of systematic sampling, including speed and reduced researcher bias.
Opportunity sampling as the easiest and fastest method but with potential for researcher bias and unrepresentative samples.
The concept of volunteer sampling and its reliance on self-selection of participants.
Concerns with volunteer bias and the challenge of generalizing findings from volunteer samples.
Stratified sampling as a complex method aiming for representativeness of the population.
The benefits of stratified sampling in ensuring representativeness and avoiding researcher bias.
Challenges with stratified sampling, including the potential for bias in strata selection and the time-consuming process.
Critique of psychology studies focusing on WEIRD (Western, Educated, Industrial, Rich, and Democratic) participants.
The implications of WEIRD participant bias on the generalizability of psychological findings globally.
Historical gender bias in psychological studies and its impact on accepted theories.
Resources available for further study on research methods in psychology.
Acknowledgment of supporters and the role of community in developing educational content.
Transcripts
This research methods in psychology video is Sampling. When researchers conduct studies,
and then publish findings it's tempting to think the findings apply to all of us. But we need to
think carefully about who exactly took part in the study, and if the behaviour of those participants
can be genralised to everyone. So in this video we will be looking at 5 sampling techniques Random,
Systematic, Stratified, Opportunity and Volunteer. We will of course also consider the strengths and
weaknesses of each. INTRO
Our first definition is for the term target population, this is every individual that forms
part of the group you plan to study. So likely to be a very large number, if you are investigating
pensioners, or four year old children, or sixth form students we won't be able to test all of
them, we need to take some of them, a sample. What we hope to do when we get our results
from the sample, is apply the results back to the target population, this is called generalisation.
However, members of a population vary in many ways, so ideally we want a sample that is
representative of the larger population. Random
So let's start with random sampling, now it's not just grabbing anyone to take part in your study,
it's mathematically random, so everyone in the population has the same chance or
probability to be selected as a member of the sample. A researcher first needs a list
of all members of the population. And then use a method of selecting them randomly. So putting
the names into a hat and drawing them out until they have a full sample, or giving each name a
number and using a random number generator. The strength of this method is it avoids
researcher bias. The researcher can’t just choose the people they want in the study,
which could influence the results. However because it is random,
we could randomly get an unrepresentative sample, maybe not representing all minority groups.
If the population size is large a random sample can be time consuming,
Systematic Systematic sampling is similar to random, we
still need the list of the population, but instead of picking randomly, we go down the list and
choose every 5th or 10th or Nth person. You can imagine a teacher picking a sample from her class
using the register and calling out every 3rd name. This again removes the chance for researcher bias
in picking who they want in their studies. And with a small population studied, and lists of the
population already exist, such as with the register can be a quick way of getting a sample
It's unlikely but still possible to to get an unrepresentative sample using a
systematic approach, and with large populations it's difficult to get a full list of members.
Opportunity An opportunity
sample is the easiest sample to get and most commonly used. The researcher simply includes
anyone in the sample that they can get their hands on by simply asking them to take part.
For that reason many psychology studies are actually conducted on university students.
A strength of this of course is it's a much faster way of getting a sample than
other methods. This could save money and allow the researcher to complete the study faster.
But there are big problems with an opportunity sample. There is the potential for researcher
bias. The researcher decides who to ask and who not to ask, potentially manipulating
the results. Also the sample is likely not representative as the researcher only has
access to a limited section of the population, in most cases, young university students.
Volunteer Another word for a volunteer sample
is a self selecting sample. This makes clearer the important factor of this sampling method,
that the participants select themselves , they volunteer themselves. They are not
directly asked. So they may see an advert in the newspaper or online and put themselves forward.
So a strength of this is by using an advertisement, especially in a popular newspaper,
the researcher can reach a large number of potential participants. And is relatively
easy to collect as after placing the ad, the participants are putting themselves forward.
but we have the issue of volunteer bias, people who volunteer for studies are a
certain type of person. They are of course helpful, and they have the time to take
part in psychology studies. But we want to include people who are unhelpful, and people
who are busy. If we don't we may not be able to generalise our findings to the wider population.
Stratified A stratified sample is the most
complex type of sample, but it tries to avoid some of the problems of the other methods. A stratified
sample creates a sample that is representative of the population as a whole. So firstly the
researcher will identify subgroups, or strata and their proportion in the wider population.
Then the sample is made by randomly selecting participants from within each strata
so they are represented in the same population in the final sample. So if 10% of your population
were university graduates, 10% of your sample would be university graduates.
The big positive of this approach to sampling is the sample is representative of the larger
population, meaning we can be confident in genralising what we find to the population.
Also this sampling method avoids researcher bias as it randomly
selects participants from within each strata. But the researcher does decide what strata are
important to consider, meaning there may be some bias in the selection of strata,
and as you can imagine stratified sampling is time consuming and difficult.
Bouns fact - WEIRD participants So when considering sampling we
need to consider the implications of bias and generalisation. I've already told you
what genralisation is and about researcher bias and volunteer bias. But going a little deeper,
a critisicm of psychology studies is most of them have been completed on WEIRD participants.
And by weird I mean most participants of from a western, educated, industrial,
rich and democratic background. In fact if you are an American university student you are 4000
times more likely to be in a psychology study than a random non westerner. This leads us to
consider if much of what we know about psychology actually applies, or genralises around the world.
Also the samples of historical studies, often ignored or underrepresented women,
leading us to also consider gender bias in much of accepted psychological theory.
Outro So that was Sampling,
I have 6 tutorial videos covering the 2017,18 and 19 AS and A-level research methods sections,
these videos have worked examples to every question and are full of exam tips. Patrons
at the neuron level and above can access these, and many, many more hours of exam tutorial videos,
as well as over a hundred printable resources from across the A-level over on psych boost .com
I do want to thank all the students and teachers who have supported psych boost
over on patreon during the development of the research methods unit. It's their
support that allows me to teach part time so I can make psych boost on youtube for everyone.
So thanks to them, and I will see you all in the next research methods video,
experimental design.
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