RESEARCH METHODS Flashcards
Aim
The aim is a statement outlining the purpose of the investigation. It can range in length from a single sentence to a short paragraph and should be expressed as clearly and precisely as possible. Some examples of appropriate research aims are:
- The aim of this investigation is to compare differences in the amount of sleep obtained by adolescents and very old people
- The aim of this experiment is to assess the effects of practice on learning
- To examine the effects of acronyms on recall
Independent Variable (IV)
The variable in an experiment that is systematically changed or manipulated by the experimenter in order to measure its effect on the dependant variable.
Dependant Variable (DV)
The variable in an experiment that is observed or measured and is expected to change as a result of the manipulation of the IV. It DEPENDS on the changes of the IV.
Controlled Variables
A controlled variable is one that is considered to have an effect of the Dependent Variable in an experiment so it needs to be held constant (controlled) to remove its potential effects.
A controlled variable is not part of the experiment i.e. it is not relevant to the aim or hypothesis. But it is controlled because it could influence the outcome.
Hypothesis
A tentative and testable prediction of the relationship between two or more events or characteristics.
- There are two different types - a RESEARCH Hypothesis which is basic and simply states that one event or characteristic (variable) influences, causes or contributes to a second event or characteristic (another variable).
Eg. Exercise relieves Depression. - Or an OPERATIONALISED Hypothesis which is more complex and states EXACTLY how the variables will be measured.
Operationalised Hypothesis/Operationalising
Step 1: Operationalise Variables → defining how they will be manipulated of measure in the investigation.
Step 2: Creating a hypothesis:
Exercise relieves Depression.
becomes:
Teenagers who run 5km each night (IV) will decrease the number of negative words used when writing a creative story (DV) compared to those who do not run.
This shows exactly what will be studied and how in order to test the initial idea, that exercise relieves depression.
Hypothesis Template
It is hypothesised that POPULATION who IV (condition 1) will DIRECTION the DV compared to IV (condition 2)
Sample
SAMPLE = a group that is a subset or part of a larger group chosen to be studied for research purposes.
Population
POPULATION = The term which describes the larger group from which a sample is selected and to which the will seek to apply or generalise the results.
Sampling
Sampling is the process by which a subset or part of the population is selected for an investigation. The population of research interest is often referred to as the target population.
Researchers aim to have a representative sample, that is, one that closely represents the population in key characteristics. If it does not it is known as a biased sample.
Types of Samples
- Random sampling
- Convenience sampling
- Stratified sampling
Convenience sampling
CONVENIENCE SAMPLING (or, Opportunity Sampling):
= Selecting participants who are readily available without any attempt to make the sample representative of a population. Quick, cheap, simple but cannot be generalised to a wider population. Often used as a pilot or a test study.
Eg. use of other students at the school, or the first people you come across who meet your requirements.
Random sampling
RANDOM SAMPLING
= A procedure of selection that ensures each member of the population has an equal chance of being selected. Eg. Using electoral roll, names out of a hat etc.
Advantages:
- It helps ensure a highly representative sample, allowing for greater confidence in generalisations (however this is not always guaranteed.
Limitation:
- It can only truly be carried out if a complete list of the target population is available.
Stratified sampling
STRATIFIED SAMPLING
= Involves dividing the population into subgroups or strata, then selecting a separate sample from each strata in the same proportions as they occur in the target population.
Random allocation
RANDOM ALLOCATION:
= Participants have as much likelihood of being in one group as they do another.
Random allocation can be achieved by flipping a coin, drawing names out of a hat etc.
By doing this, the researcher can be more confident to say that any change in behaviour/thoughts at the end of the experiment is as a result of the independent variable.
Control group
CONTROL GROUP
= exposed to the condition where the independent variable is absent. Provides a baseline for comparison.
Experimental group
EXPERIMENTAL GROUP
= exposed to the condition where the independent variable under investigation is present.
Controlled Experimental Designs
- Between Subjects
- Within Subjects
- Mixed Design
Between Subjects Design
(previously called Independent Groups)
= where each participant is randomly allocated to one of two or more entirely separate groups.
Advantages:
- Can usually be completed at one time
- No order effects
Limitations:
- Less control over participant variables
- Larger sample needed
Within Subjects Design
(previously Repeated Measures)
= a design that uses the same participants in both the experimental and control groups (or conditions). That is, the same group is used a number of times.
Advantages:
- Control of participant variables
- Smaller sample can be used
Disadvantages:
- Order effects
- Participant expectations
- Higher drop-out rates
- More time consuming
Mixed design
Combines features of both a between subjects design and a within subjects design. This means that the researcher can assess the potential differences between two or more separate groups of participants (i.e. between subjects) as well as change in the individual members of each group over time (i.e. within subjects).
The main advantage of the mixed design is that the researcher can capitalise on the strengths of the between subjects and within subjects designs.
- Fewer participants are needed for the experiment and there is greater sensitivity in the results; that is, they tend to be more precise and detailed.
Non-Experimental Studies
- Correlation Studies
- Self-Reports
- Observational Studies/Fieldwork
- Case Studies
- Simulation Studies
Correlational Study
A correlational study is used to investigate the relationship that exists between variables without any control over the setting in which the relationship occurs or any manipulation by the researcher. There are no IVs or DVs, or control groups, nor can the researcher randomly assign participants to different conditions. The researcher merely measures the relationship between the variables of interest with no intervention.
- A positive correlation means that two variables change (‘vary’) in the same direction — as one variable increases, the other variable tends to increase (and vice versa).
- A negative correlation means that two variables change in opposite directions — as one variable increases, the other variable tends to decrease (and vice versa). As BAC increases, reaction time decreases.
- A zero correlation means that there is no relationship between two variables. For example, there is no relationship between the amount of coffee drunk and VCE grades.
Strengths and limitations of Correlational Study
STRENGTHS:
- Used to test hypotheses in cases where it is not desirable or possible to experimentally manipulate the IV of interest.
- Suitable alternative when an experiment is inappropriate for ethical reasons or impractical.
- Useful for discovering relationships between variables, even if not causal. In particular, they can identify variables that are more or less important or worthwhile for further study and investigation.
LIMITATIONS:
- Do not permit the researcher to draw firm conclusions about cause-and-effect relationships.
- Difficult or impossible to control unwanted variables, such as a third variable (or others) that may offer a possible alternative explanation.