Research Methods Flashcards
What is the definition of a population?
A group of people who are the focus of the researchers interest, from which a smaller sample is drawn.
What is the definition of a sample?
A group of people who take part in a research investigation.
Where is a sample drawn from?
From a target population and is presumed to be representative of that population.
What is the definition of bias?
When certain groups are over- or under-represented within the sample selected.
What is the negative effect of bias?
It limits the extent to which generalisations can be made to the target population.
What is the definition of generalisation?
The extent to which findings and conclusions from a particular investigation can be broadly applied to the population.
When is generalisation possible?
If the sample of participants is representative of the population.
Why is it often called a ‘target population’?
It is a subset of the general population.
Why are samples used?
For practical and economic reasons, it is usually not possible to include all members of a target population -> researcher uses a smaller group.
What should samples ideally be and why?
Representative of the target population so that generalisation of findings become possible.
Why is it often very difficult to represent populations?
Due to the inevitably diverse nature of populations, e.g, different age, ethnicity, gender.
What are the 5 main sampling techniques?
Random sampling, Systematic sampling, Stratified sampling, Opportunity sampling, Volunteer sampling.
Why are sampling techniques used?
In attempt to produce a representative sample.
What is a random sample?
A form of sampling in which all members of the target population have an equal chance of being selected.
What are the steps of random sampling?
1- Obtain a complete list of all members of the target population.
2- All the names of the list are assigned a number.
3- The actual sample is selected through the use of some lottery method - a computer/phone randomiser or picking numbers from a hat.
What is a systematic sample?
When every nth member of the target population is selected.
What is produced in systematic sampling and what is it?
A sampling frame - a list of people in the target population that are organised some way.
What happens after a sampling frame is produced in systematic sampling?
A sampling system is nominated (e.g, every 3rd person) and the researcher then works through the sampling frame until the sample is complete.
What is a stratified sample?
A form of sampling in which the composition of the sample reflects the proportions of people in certain subgroups within the target population/wider population.
What are the steps of stratified sampling?
1- The researcher identifies the different strata that make up the population.
2- The proportions needed for the sample to be representative are worked out.
3- The participants that make up each stratum are selected using random sampling.
What is an opportunity sample?
Where the researcher simply takes the chance to ask whoever is around at the time of their study to participate, e.g, in the street.
What is a volunteer sample?
Involves participants selecting themselves to be part of the sample.
How would a volunteer sample potentially be selected?
A researcher may place an advert in a newspaper or on a common room noticeboard.
Strength of a random sample and why?
Potentially unbiased - means that confounding variables or extraneous variables should be equally divided between the different groups - enhancing internal validity.
Limitation of a random sample and why?
Difficult and time consuming to conduct as a complete list of the target population may be difficult to obtain.
Strength of a systematic sample and why?
It is objective, as once the system for selection has been established, the researcher has no influence over who is chosen.
Limitation of a systematic sample and why?
Time-consuming, and in the end, participants may refuse to take part.
Strength of a stratified sample and why?
Produces a largely representative sample, because it is designed to accurately reflect the composition of the population = generalisation of findings becomes possible.
Limitation of a stratified sample and why?
It is not perfect. The identified strata cannot reflect all the ways that people are different, so complete representation of the target population is not possible.
Strength of an opportunity sample and why?
Convenient. Much less costly in terms of time and money as a list of members of the target population is not required + there is no need to divide the population into different strata (like in stratified).
Limitation of an opportunity sample and why?
Suffers from two forms of bias.
1- The sample is unrepresentative of the target population as it is drawn from a very specific area.
2- The researcher has complete control over the selection of participants = researcher bias.
Strengths of a volunteer sample and why?
Easy. It requires minimal input from the researcher and so is less time-consuming.
The researcher ends up with participants who are more engaged.
Limitation of a volunteer sample and why?
Volunteer bias. Asking for volunteers may attract a certain ‘profile’ of person, that is, one who is curious and more likely to try to please the researcher.
What is a case study and how is it usually carried out?
An in-depth study of one person or a group of people over time.
It is usually carried out in the real world and is usually longitudinal.
What are the techniques used in a case study?
- IQ testing.
- Personality testing.
- Observations.
- Interviews.
- Experiments.
- Medical case notes.
How are the findings of case studies organised?
Into themes to represent the individuals thoughts, emotions, experiences and abilities.
How is data from a case study often presented?
In a qualitative way - though quantitative date may also be included, e.g, scores from psychological tests.
What should be maintained in a case study and how?
Confidentiality. By making sure individuals are not identifiable - could be done by using a different name/initials, and by not publishing details of an address, ect.
Advantages of case studies?
1- Rich data.
2- High ecological validity.
3- Investigates situations which could not be set up for ethical reasons.
How are case studies rich in data and how is this a strength?
As case studies are usually longitudinal, a large amount of data is gathered over a long period of time. Strength = gives great depth and understanding of an individual/group.
How do case studies have high ecological validity and how is this a strength?
Usually longitudinal and the p.p/group is often studied in their own environment. Strength = case studies have high external (ecological) validity.
How do case studies investigate situations which could not be set up for ethical reasons and how is this a strength?
Often investigate naturally occurring events that would be unethical to test during an experiment. Strength = they can provide insight into areas of psychology that we wouldn’t be able to investigate in any other way.
Limitations of case studies?
1- Findings cannot be generalised very easily to other individuals.
2- Difficult to replicate.
3- Researcher bias.
How can case study findings not be easily generalised to other individuals and how is this a limitation?
Each individual/group and their experience is unique so case studies may only represent the behaviour of one group/person. Limitation = may be difficult to generalise the results to others.
How are case studies difficult to replicate and how is this a limitation?
Case studies are very unique. Limitation = it is not possible to test the external reliability of the findings.
How do case studies involve researcher bias and how is this a limitation?
Usually longitudinal, so researchers may get to know the individual well which may lead to a loss of objectivity. Limitation = if this were to happen it would reduce the internal validity of the study.
What are investigator effects?
Any effect of the investigators behaviour (conscious or unconscious) on the research outcome (DV).
What may investigator effects include?
Everything from the design of the study to the selection of, and interaction with, participants during the research process.
What is randomisation?
The use of chance methods to control for the effects of bias when designing materials and deciding the order of experimental conditions.
What is standardisation?
Using exactly the same formalised procedures and instructions for all participants in a research study.
What is the definition of experimental design?
The different ways in which participants can be organised in relation to the experimental conditions.
What is the definition of independent groups (IG) design?
Participants are allocated to different groups where each group represents one experimental condition.
How does independent groups design work?
Two separate groups of participants experience two different conditions of the experiment. The performance of the two groups would then be compared.
What is the definition of repeated measures (RM) design?
All participants take part in all conditions of the experiment.
How does repeated measures design work?
All participants experience both conditions of the experiment. The results from both conditions would be compared.
