Research methods

Extraneous variable
Any variable other than the IV that may affect the DV that may occur at a random point in the experiment
Confounding variable
Any variable other than the IV that has a systematic effect on the DV throughout the experiment.
Independent Variable
A variable manipulated to test the effect on the DV
Dependent variable
A variable that is measured to test the effect of the manipulation of the IV
Control Group
Is not exposed to the IV; serves as a baseline measure
Experimental Group
The group that has been exposed to the IV
A fake treatment given to the control group to control participant expectancy
Placebo effect
The expectations of participants have affected the DV
Experimenter effect
The actions of the experimenter have affected the DV
1/2 the participants to control condition 1st the other 1/2 do the experimental condition 1st, then they swap, which cancels out the order effect
Single blind procedure
The experimenter allocates subjects to either the control or experimenter group so that subjects are unaware of their group, thus eliminating the placebo effect
Double blind procedure
An assistant allocates subjects to either the control or experimental group so that both the experimenter and subjects are unaware of their group, thus eliminating the experimenter group.
A subset of the population of interest
Random allocation
All members of the sample have an = chance of being in the control or experimental group
Independent groups
subjects are randomly allocated to either the control or experimental condition
Matched pairs
Subjects are pre-tested and then paired together on a characteristic(s) relevant to the study & then one from each pair is allocated to either the control or experimental condition
Repeated measures
Subjects are exposed to both the control condition and experimental condition
Operational hypothesis
Is a statement of the predicted effect of change in the IV on the value of the DV
Convenience sampling
Selecting readily available subjects from a population, with no effort to acquire subjects that are representative of the population
Random sampling
Allocates members from a population to the group involved in an experiment, so that every member has an = chance of being selected
Stratified sampling
The population is divided into groups based on chacteristics relevant to the experiment (e.g. age/gender). The group used for testing matches the proportions of these categories of interest
Order effect
Where the sequence in which conditions were performed (for a repeated measures design) may have an extraneous effect on the DV
Is the body of the community from which a sample of participants is drawn
Stratified random sampling
The poulation is divided into catergories of interest (e.g. age, IQ), then subjects are randomly allocated from each category to match the proporations (of each category) used for the population of interest
Code of ethics
Provides a set of guidelines that must be followed when experimenting on animals/ humans
The researcher has the responsiblity to maximise possible benefits and minimise potential risks
Any negative consequences of participation in the experiment must be extinguished during this process
Withdrawal rights
Subjects have the right to remove their results at the conclusion of the study
The ethics committee must give researchers permission to not fully inform subjects of the procedures used in an experiment
Voluntary participation
Participants should not be coerced into participating in a study