research methods Flashcards
aim
purpose of study
hypothesis
statement outlining the probable outcome of an investigation
It is hypothesised that the IV (experimental group) will affect (strength/direction) the DV compared with the IV (control group)
independent variable
variable that is manipulated/controlled/changed
dependent variable
the variable that is measured
extraneous variables
variables other than the iv that have unwanted effects on the dv and results
e.g
- individual differences between participants
- differences in experimental settings between groups
- experimenter influences
- practice
controlled variables
variables that are held constant to ensure that the only influence on the dependent variable is the independent variable
confounding variables
unwanted variables that affect the DV and results in an investigation, and it cannot be determined whether the IV or the confounding variable caused the change in the DV.
population
the wider group of people that a study is investigating
sample
the smaller group of people selected from the population who will be participants in the investigation
random sampling
selecting participants from the population in such a way that each member of the population has an equal chance of being selected
+/- of random sampling
strengths:
- a large enough random sample is likely to be representative of the population, improving external validity
limitations:
- small random samples may not be representative of the population, reducing external validity
- it may be difficult, time consuming, impossible or unethical to obtain names of all members of the population
stratified sampling
dividing the population into subgroups, then randomly selecting participants from each subgroup in the proportion that they appear in the population
+/- stratified sampling
strengths:
- a large enough stratified sample is likely to be representative of the population, improving external validity
- important subgroups of a population are ensured fair representation
limitations:
- it may be difficult, impossible or unethical to obtain names of all members of the population
- it is more time-consuming than using a random sampling technique because of the need to form subgroups and any pre-testing required
investigation methodology
type of research study
controlled experiment
investigation methodology that aims to test the effects of the IV on the DV with all other variables controlled
+/- controlled experiment
strengths:
- controlled experiments can identify a cause-and-effect relationship between an IV and a DV
- results may be generalised to the population of interest if the study is deemed to have good validity
- controlled experiments can be repeated to gather more data and test the reproducibility and repeatability of results
limitations:
- controlled experiments require strictly controlled conditions, which may be difficult to maintain, so results may be influenced by extraneous variables
- participant behaviour may be influenced by the artificial nature of the setting
- it may be unethical or impossible to conduct a controlled experiment on a particular variable
- external validity may be low if the conditions are too artificial to extrapolate results to the population of interest outside the experiment
random allocation
involves dividing the sample into groups in such a way that each participant has an equal chance of being placed into the experimental group or the control group
investigation design
involve different ways that participants experience the experimental and control conditions
between subjects design
participants are randomly allocated to either the control or experimental condition
+/- between subjects design
strengths:
- a between-subjects design is the most time efficient design because both groups can be tested at the same time and no pre-testing is required
- It has a lower rate of participant withdrawal than a within-subjects design because participants only complete one condition.
- There is better control of participant knowledge of the study and there is no effect of prior participation extraneous variables influencing results compared with a within-subjects design.
limitations:
- More participants are needed in a between-subjects design than a within-subjects design.
- There is less control over the extraneous variable of participant variables between groups, which may influence results in an unwanted way, lowering validity.
within-subjects design
all participants in the sample complete both the experimental and control conditions
+/- within subject design
strengths:
- In a within subjects design, there is no extraneous variable of participant variables between groups, improving validity.
- Fewer participants are needed than in a between subjects design.
limitations:
- There is less control over participant knowledge of the study. The extraneous variable of prior participation in the first condition may influence their behaviour while completing the second condition.
It is more time-consuming than a between-subjects design because both conditions cannot be tested at the same time.
- There is a higher rate of participant withdrawal from the study than in a between-subjects design because the DV has to be measured multiple times.
mixed design
combination of a between-subjects design and a within-subjects design
For example, in an investigation testing whether male or female students benefit from listening to classical music or pop music while studying for a test, the between subjects element is whether the student is male or female, and the within subjects element is listening first to classical music and then to pop music while studying.
+/- mixed
strengths:
- Differences in participant variables between groups are controlled in the within-subjects design element.
- Can test the effect of multiple independent variables on a dependent variable in one investigation.
- Testing multiple independent variables in one investigation can be time and cost-effective compared to completing two or more separate investigations
limitations:
- There is a higher rate of participant withdrawal from the study than using a between-subjects design alone, which can be detrimental to the internal validity.
- There is less control over participant knowledge of the study. Prior participation in the first condition may influence their behaviour while completing the second condition, than when using a between subjects design alone.
- There is less control over differences in participant variables between groups in the between subjects element, which may influence results in an unwanted way, lowering validity.
case study
Investigation of a particular activity, behaviour, event or problem that contains a real or hypothetical situation and includes real-world complexities.
+/- case study
strengths:
- Case studies are useful when a limited number of participants are available.
- They can be used to study experiences where it would be unethical or impossible to design and conduct a controlled experiment.
- They can provide rich qualitative data.
- They can act as a basis for further research.
Limitations:
- One person or a small group of people cannot be representative of a population, so results from a case study cannot be generalised to the population, and there is a low external validity.
- Researcher bias may influence the recording, collation and treatment of data.
- They may not be repeatable to gain more data or to test reliability of results.
- They are typically time consuming.
classification and identification
involves two distinct components. Classification in research involves arranging phenomena, objects or events into manageable sets.
Identification involves recognising phenomena as belonging to a particular set or being part of a new or unique set.
+/- classification and identification
strengths:
- Classifications can allow for a narrowed focus of research.
- People identified as having a similar classification can feel a sense of belonging and support.
- Using classifications can allow for efficient processing of large amounts of information.
- Classifications can help make predictions and inferences.
limitations:
- Labelling through identification can lead to stereotyping, prejudice or discrimination.
- Classifications may be based on subjective criteria.
- Large amounts of information are required to create classifications.