Confounding Variable
Any variable which varies systematically with the independent that might potentially affect the dependent variable and thereby
... [Show More] confound results.
Operationalise
Ensuring variables are in a form than can be easily tested.
Standardised Procedures
A set of procedures that are the same for all participants in order t be able to repeat the study.
External Validity
Degree to which a research finding can be generalised to:
- other settings (ecological validity)
- other people (population validity)
- over time (historical validity)
Extraneous Variables
Affect the dependent variable but not in a systematic way. They should be controlled if possible.
Pilot Study
Small scale trial run of a study to test any aspects of the design, with a view to making improvements.
Aim of Research
A statement of what the researcher(s) intend to find out in a research study.
Hypothesis
A precise and testable statement about the assumed relationship between variables. Operationalisation is a key part of making statement testable.
Internal Validity
Degree to which an observed effect was due to experimental manipulation rather than other factors.
Independent Variables
An event that is directly manipulated by an experimenter in order to test its effect on the dependent variable.
Experiment
Causal conclusion can be drawn because an IV has been deliberately manipulated to observe a causal effect on the DV.
Quasi-Experiment
Studies that are 'almost' experiments. Experimenter has not manipulated the IV directly. The IV would vary whether or not the researcher was interested and researcher records the results.
Natural Experiments
Experimenter cannot manipulate the IV directly, but where it varies naturally, and the effect on the DV can be observed.
Participant Observation
Observations made by someone who is also participating in the activity being observed, which may affect their objectivity.
Non-Participant Observation
The observer is separate from the people being observed.
Content analysis
A kind of observational study in which behaviour is observed indirectly in written or verbal material such as interviews, conversations, books, diaries or TV programmes.
Semistructured interview
The interview starts out with some general aims and possibly some questions and let ls the respondents answers guide subsequent questions.
Case study
Research investigation involves a detailed study of a single individual, institution or event. Provides a rich record of human experience but hard to generalise from.
Self-report
Data collection techniques where participant describes their behaviour, for examples questionnaires, interviews or studies.
laboratory
An environment which can be controlled by the researcher. In particular a researcher wishes to control extraneous variable and, in an experiment, needs to manipulate the independent variable.
The field
Conducting research in the field usually means working with participants in an environment that is more familiar to them i.e a more natural setting.
Online
Refers to being connected via the Internet to another source. You may be connected to a website or could be using an app. Data can be collected from individuals.
Target population
The group of people that the researcher is interested in. The group of people from whom a sample is drawn. The group of people about whom generalisations can be made.
Sampling frame
Source material from which sample is drawn
Random sampling
Sample of participants produced by using a random technique such that every member of the target population being tested has equal chance of being selected
Opportunity sampling
A sample of participants produced by selecting people who are more easily available at the time of the study.
Systematic sampling
Sample obtained by selecting every nth person. This can be a random sample if the first person is selected using a random method; you then select every nth person after that.
Stratified sampling
Sample of participants produced by identifying subgroups according to their frequency in the target population. Participants then selected randomly from the subgroups.
Self-selected sampling
Sample of participants that rely solely on volunteers to make up a sample.
Snowball sampling
Relies on referrals from initial participants to generate additional participants.
Event sampling
Observational technique in which a count is kept of the number of times a certain behaviour occurs.
Time sampling
An observational technique in which the observer records behaviours in a given time frame. The observer may select one or more behavioural categories to tick at this time interval.
Independent groups design
Participants are allocated to two or more groups representing different levels of the IV. Allocation is usually done using random techniques.
Repeated measures
Each participant takes part in every condition under test i.e. each level of the IV.
Matched pairs
Pairs of participants are matched in terms of key variables such as age and IQ. One member of each pair is allocated to one of the conditions under test and the second person allocated the other condition.
Nominal data
Data is in separate categories.
Ordinal data
Data is ordered in some way.
Interval data
Units are equal interview intervals are used, such as counting correct answers.
Measures of central tendency
Please inform us about central values for set of data. They are averages - ways of calculating typical value for set of data. Mean, Median, Mode.
Mean
Calculated by adding up all the data items and dividing by the number of data items. It's the most sensitive as it takes into account every value of data, this means it can be easily distorted by one, or a few, extreme values and thus, end up being misrepresentative of the data as a whole.
Median
The middle value in an ordered list. The median can be used with ratio, interval and ordinal data. The median is not affected by extreme scores, that can be useful in certain circumstances. It's also not sensitive like the mean because the exact values are not reflected in the median.
Mode
The value that is the most common data item. In nominal data it is the category that has the highest frequency count. In interval and ordinal data it is the data item that occurs most frequently. It is unaffected by extreme values.
Measures of Central Dispersion
How dispersed are spread out the data items are.
Range
The distance between the top and bottom bottom values in a set of data. The top number minus the bottom number +1. It's affected by extreme values and fails to take into account the distribution of the numbers.
Standard deviation
Precise measure of dispersion as all the exact values are taken into account.
Internal reliability
Measure of the extent to which something is consistent with itself.
External reliability
The extent to which a measure varies from one occasion to another. Low external reliability would mean there is quite a bit of variation over time.
Demand characteristics
A cue that makes participants unconsciously aware of the aims of the study or help participants work out what the researcher expects to find out.
Researcher bias
Anything the investigator does that has an affect on the participants performance in a study other than what was intended. Investigator effects may act as a confounding or extraneous variable.
Longitudinal study
Study conducted over a long period of time. Often a form of repeated measures design in which participants are assessed over two or more occasions as they get older. However some longitudinal research is not experimental, people may simply be observed for a number of years.
Cross-sectional studies
One group of participants representing one section of society, for example young people, are paired with participants from another group, for example old people.
Inter-rater reliability
The extent to which there is agreement between two or more observers involved in observations of behaviour.
Test retest reliability
Used to check external reliability. The same test or interview is given to the same participants on two occasions to see if the same results are obtained.
Split half reliability
Method of assessing internal reliability by comparing two halves of, for example, a psychological test to see if they produce the same score
Concurrent Validity
Means of establishing external validity by comparing an existing test or questionnaire with the one you are interested in.
predictive validity
Correlating the results of a test with some other example of the behaviour that is being tested.
Face validity
Form of external validity, the extent to which test items look like what the test claims to measure.
Content validity
Aims to demonstrate that the content of a test on measurement represents the area of interest.
Construct validity
The extent to which performance on the test measures and identified underlying construct.
CT scan
Uses a series of x-ray beams passed through the head, creating cross-sectional images of the brain showing the structure but not the function.
Pet scan
Scanner detects radioactive material that is injected or inhaled to produce an image of the brain.
Once in the bloodstream, it flows through the brain, oxygen and glucose accumulate in brain areas that are metabolically active.
As glucose is used in the active parts of the brain, the radioactive material breaks down and gives off a neutron and positron.
When a positron hits an electron both are destroyed and to gamma rays are released.
Gamma-ray detectors record the brain area where the gamma rays are emitted.
This method provides a functional view of the brain.
MRI
Uses detection of radio-frequency signals produced by displaced radio waves in a magnetic field it provides an anatomical view of the brain.
Advantages of MRI
- No x-rays of radioactive material used.
- Provides detailed view of the brain in different dimensions.
- Safe, painless, non-invasive.
Disadvantages of MRI
- expensive to use
- cannot be used in patients with metallic devices, like pacemakers.
- can't be used with uncooperative or claustrophobic patients.
EEG
The recording of electrical activity along the scalp produced by the firing of neurons.
fMRI
Detects changes in blood flow to particular areas of the brain. Provides both an anatomical and functional view of the brain.
Angiography
Involves a series of x-rays after dyes injected into the blood. Provides an image of the blood vessels of the brain. [Show Less]