Research Methods Flashcards
Independent variable
The variable the experimenter manipulates
Dependent variable
The variable that’s measured after making changes to the IV
Extraneous variable
Any variable that you’re not investigating that can potentially affect the outcomes of your research study
Confounding variable
Factors other than the independent variable that may cause a result
Operational hypothesis
A testable prediction that explains exactly how the variables will be measured and manipulated
Directional hypothesis
Indicates a direction in the prediction e.g., ‘students with pets perform better than students without pets’
Non-directional hypothesis
Does not indicate a direction in the prediction e.g., ‘owning pets will affect student’s exam scores’
Null hypothesis
States that there is no relationship between the 2 variables being studied e.g., ‘plant growth is not affected by light colour’
Alternative hypothesis
States that there is a relationship between the two variables being studied
Lab experiment
An experiment conducted under highly controlled conditions where accurate measurements are possible
Field experiment
A study that is conducted outside the laboratory in a “real world” setting
Natural experiment
The study of a naturally occurring situation as it unfolds in the real world
Case studies
In-depth investigations of a single person, group, event, or community
Experimental method
Manipulating one variable to determine if changes in one variable causes changes in another variable
Correlational study
Non-experimental, studies the relationship between 2 variables with the help of statistical analysis
Replicability
The ability to check and verify scientific information
Validity
The extent to which a test measures what is claims to measure
Face validity
Whether the test appears (at face value) to measure what it claims to
Internal validity
Whether the effects observed in a study are due to the manipulation of the IV and not some other factor
External validity
The extent to which the results of a study can be generalizd to other settings, other people and over time
Ecological validity
Whether the results of a study can be generalized to real life settings
Reliability
Refers to the consistency of a measure
Independent-groups design
Involves randomly allocating the members of the sample to either the control or experimental group
Matched-participant design
Involves pairing each participant based on a certain characteristic they share. Once you’ve matched these PPs, you randomly allocate one to the control group and one to the experimental group
Repeated-measure design
Involves using only one group of PPs and exposing them to both the control and experimental conditions
Random sampling
Everyone has an equal chance of being selected
Opportunity sampling
People who are available from the population
Self-selecting sampling
Using an ad (for example) and let participant’s volunteer
Stratified sampling
Put people into a group and take people from these groups. The number from each group must match proportion of population
Counter-balancing
Dividing the group of PPs in half and arranging the order of the conditions so that each condition occurs equally in each position
Placebo effect
A phenomenon to which some people experience a benefit after the administration of an inactive “look-alike” substance or treatment
Standard deviation
A measure of variation (or variability) that indicates the typical distance between the scores of a distriubtion and the mean
Demand characteristics
If the PPs know what the study is, they may alter their behaviour to give the desired outcome
Experimenter bias
The experimenter sets up the experiment in a subjective way to confirm their theory
Statistical significance
Whether the results were due to the variables, or by chance
P > 0.05
Not statistically significant and indicates strong evidence for the null hypothesis, meaning we should retain the null hypothesis and reject the alternative hypothesis
P ≤ 0.05
Indicates strong evidence against the null hypothesis as there is a less than a 5% probability the null is correct, therefore we reject the null hypothesis and accept the alternative hypothesis
Independent-groups design - Criticism
There may be participant differences between the groups, for example one group may (by coincidence) be more intelligent than the other group
Matched-participant design - Criticism
Involves a pre-test to match PPs, thus can be time consuming
Repeated-measure design - Criticism
Creates the problem of order effects - occur when there is a change in results due to the sequence that 2 tasks are completed
