research methods - em1 Flashcards
what do all experiments have?
an independent variable, a dependent variable, conditions
define variable
things that can be changed or altered
define independent variable
the variable that is manipulated to observe its effects
define dependent variable
the variable that is measured and affected by the IV
define operationalisation
clearly specifying/turning abstract concepts into measurable observations
define hypothesis
a testable statement about the relationship between the variables that are going to be studied
what is a directional/one-tailed hypothesis?-
states the direction of the difference/relationship between variables, used when there is previous research to suggest a direction
define non-directional/two-tailed hypothesis
predicts that a difference will exist between variables without predicting the exact difference
define target population
the group that the researcher draws the sample from & attempt to generalise the findings to
define sampling bias
when a sample is mainly made up of one particular type of person
define sample
a group of people that are drawn from the target population to take part in an experiment
define representative sample
a sample that closely matches the target population
define generalise
applying results to a wider population beyond the research participants
what are the methods of random sampling?
-pull names from a hat
-random name generator
advantages of random sampling
-everyone in the population has an equal chance of being chosen
-free from researcher bias (researcher has no input into who is chosen)
↳ sample is representative & generalisable
disadvantages of random sampling
-it’s time consuming & dificult to ensure that everyone in the population has an equal chance of being chosen
-people who are picked may be unwilling to take part
what is systematic sampling?
when a predetermined system is used to select participants
(eg: every nth person)
strengths of systematic sampling
-no researcher bias (researcher has no input into who’s chosen)
weaknesses of systematic sampling
-sample may not be representative
↳ each participant may have similar characteristics
what is stratified sampling?
-strata are identified
-subgroups are represented in proportion their occurrence within the population
strengths of stratified sampling
-this is the only sampling technique that will give a fully representative sample
↳ results can be generalised
weaknesses of stratified sampling
-difficult to identify each strata in the target population
what is opportunity sampling?
anyone who’s willing and available to take part in the study at the time is chosen
strengths of opportunity sampling
-quick and easy
-no researcher bias
weaknesses of opportunity sampling
-not representative
what is volunteer sampling?
ask people to take part/participants respond to an advert
strengths of volunteer sampling
-low effort
-little researcher bias
weaknesses of volunteer sampling
-non representative sample (usually only particular types of people volunteer)
define order effects
refers to how the order of tasks could influence the outcome
define random allocation
allocating participants to experimental conditions randomly
define participant variables
(+ examples)
individual differences between the participants may affect the dependent variable
(age, IQ)
define demand characteristics
a cue that makes participants aware of a study’s purpose & causes them to change their behaviour to match what they think is expected (please you/screw you effect)
define counterbalancing
controls for order effects in a repeated measures design:
the participant sample is divided in half, with one half completing the two conditions in one order and the other half completing the conditions in the reverse order
what are independent groups?
different groups are used in each condition of the experiment
strengths of independent groups
no order effects
less demand characteristics
weaknesses of independent groups
(+ control)
-participant variables
CONTROL: random allocation
-need more participants
what is a repeated measures design?
participants are one group and participate in all study conditions
strengths of a repeated measures design
-no participant variables
-fewer participants are required as they take part in all conditions
weaknesses of a repeated measures design (+ control)
-order effects (eg: fatigue)
CONTROL: counterbalancing
-demand characteristics
what is a matched pairs design?
-participants are paired from the sample based on similar characteristics
(eg: age & IQ)
-one member goes in condition A and the other goes in condition B
strengths of a matched pairs design
-no participant variables
-no order effects
weaknesses of a matched pairs design
-time consuming
-impossible unless identical twins are used
define extraneous variables
variables that could affect the DV
define confounding variables
extraneous variables that are important enough to change the DV
define systematic error
affect the scores of one condition differently than the other
define random error
spread randomly across the scores of both conditions
define situational variables
(+ examples)
factors connected to the research situation that could affect the DV
(eg: temp, noise)
define investigator effects
the experimenter unconsciously conveys to participants how they should behave, they could give unintentional clues about what the experiment is about
what do confounding variables lead to?
mistaken conclusions about what has affected the DV
when does an extraneous variable become a confounding variable?
if it is not controlled for at the start of the study
how can demand characteristics be controlled?
by not letting the participants guess the aim of the research
↳ single‐blind experimental
technique / independent groups
what is a single blind experimenter technique?
-only the researcher knows the true aim of the experiment
-a measure of deception has been used so that the participants cannot easily guess the aim
examples of possible cues resulting in demand characteristics:
-the instructions
-what the participant may already have heard about the study (for example, from other participants)
-the way the participant is approached initially and asked to volunteer
-the setting of the study
define standardisation
the procedures used in research are kept the same
why is standardisation important?
1) if all elements of a procedure are the same, then the methods will be sensitive to any change in performance, then changes in data can be linked to the I.V
2) the results will be replicable, which
means that data reflects a meaningful pattern and was not a chance result
what is a pilot study?
a small-scale trial run which is done before the main study to identify any problems or confusions
are the results from a pilot study included in a final analysis?
no
why is it sensible to do a pilot study?
to find any possible errors in the methodology and to modify it for the actual investigation
should a pilot study use the same participants as the main study?
no
what should a pilot study establish?
-whether the design works
-whether participants understand the
instructions and the debrief
-whether the task is too easy or hard
how do you control situational variables?
standardisation
how do you control participant variables?
random allocation or matched pairs design
how do you control investigator effects?
single blind research
how do you control order effects?
-use an independent groups/matched pairs design
-counterbalance
what is experimental design?
the way participants are allocated to experimental groups.
types of experimental design:
repeated measures, independent groups, and matched pairs
