research methods Flashcards
what is an experiment?
A testable situation that determines a cause-effect relationship between variables under controlled conditions
what is an independent variable?
the variable that is systematically manipulated by the experimenter in order to measure its effect on the DV.
what is the dependent variable?
the variable that is used to observe and measure the effects of the IV
what is an operationalised variable?
turning the IV and DV into procedures so that it can be manipulated or measured in an experiment
what is a hypothesis?
a statement or testable prediction about the direction of interaction between the IV and DV and the population from which the sample is drawn.
what is a threory?
general explanation of a set of observations or findings of behaviour and/or mental processes that seem to be related
what is a model?
representation of how some behaviours and/or mental processes could, should or do occur
define population
everyone of research interest from which the sample is selected
what is a sample?
the group of people taken from the population to be studied
what is sampling? what is the goal of sampling?
process of selecting participants for a research study to obtain a representative sample of the population from which it was selected
what is stratified sampling?
divides a population into strata (subgroups) based on particular differences in characteristics and then participants are selected from each stratum in the same proportions as they exist in the population
evaluate stratified sampling
adv:
- more representative and unbiased
- allows researcher to sample specific strata for comparative purposes
dis:
- time consuming; requires list of target population for information about population characteristics to be available
what is random sampling?
every individual in the population has an equal chance of being selected for the sample
evaluate random sampling
adv:
- more representative
- generalisations are more likely to have external validity
dis:
- still a chance the sample is unrepresentative
- requires complete list of the target population; time consuming if list is unavailable
what is convenience sampling?
selecting participants who are readily and easily available
evaluate convenience sampling
adv:
- quick, easy, inexpensive
- can be used as a test procedure or gain an indication of possible responses before the actual study
dis:
- biased sample; only those available at the time and location of the study have a chance of being included in the sample
- data obtained can be misleading= results cannot be generalised
what is a representative sample and why is a bigger sample more representative?
- sample that is approximately the same as the population in every important participant variable
- as sample size increases, the characteristics of the sample more closely reflect the characteristics of the population from which the sample was drawn
define allocation
the process of assigning participants to either the experimental group(s) or the control group
what is the purpose of the control group?
not exposed to the IV to provide a baseline of comparison for the experimental group to determine if the IV has had any effect on the DV
what is random allocation?
every participant in the sample has an equal chance of being in the experimental or control group
what is the advantage of random allocation?
- Minimises the effects of individual differences that may occur between participants
- more likely to spread the participant characteristics evenly across the two groups
what are the types of experimental designs?
- independent groups
- matched participants
- repeated measures
what is independent groups design?
different participants are used in each group of the experiment and are exposed to different conditions
evaluate independent groups design
adv:
- if random allocation and sampling is used= helps increase the likelihood of an even spread of participant characteristics between conditions
- no order effects occur as participants only complete one condition
- experiment can usually be completed on one occasion= minimal participant dropout
dis:
- least effective at controlling individual differences between conditions
- often need a larger number of participants to help the spread of participant characteristics