Research Methods
Research methods counts towards at least 25-30% of all marks.
Contents
Aims.............................................................................................................................................................3
Hypothesis...................................................................................................................................................3
Variables......................................................................................................................................................3
Research issues............................................................................................................................................4
Controlling research issues......................................................................................................................4
Experimental method..................................................................................................................................5
Types of experiment................................................................................................................................5
Experimental designs...............................................................................................................................6
Sampling......................................................................................................................................................7
Ethics...........................................................................................................................................................9
Pilot studies...............................................................................................................................................10
Observational techniques..........................................................................................................................10
Types of observation.............................................................................................................................10
Observational design.............................................................................................................................11
Behavioural categories......................................................................................................................11
Ways of recording data......................................................................................................................12
Sampling methods.............................................................................................................................12
Self-report techniques...............................................................................................................................12
Questionnaire........................................................................................................................................12
Interview................................................................................................................................................14
Designing interviews..........................................................................................................................15
Common errors in question design........................................................................................................16
Correlations...............................................................................................................................................16
Types of data.............................................................................................................................................18
Primary data..........................................................................................................................................18
Secondary data......................................................................................................................................19
Meta analysis.........................................................................................................................................19
Qualitative data.....................................................................................................................................19
Quantitative data...................................................................................................................................20
1
, Presentation of quantitative data......................................................................................................20
Distributions......................................................................................................................................21
Mathematical content...............................................................................................................................22
Peer review................................................................................................................................................23
Implications of psychological research for the economy...........................................................................24
Case studies...............................................................................................................................................25
Content analysis........................................................................................................................................26
Reliability...................................................................................................................................................27
Assessing reliability................................................................................................................................28
Improving reliability...............................................................................................................................28
Validity.......................................................................................................................................................29
Assessing validity...................................................................................................................................29
Improving validity..................................................................................................................................29
Features of science....................................................................................................................................30
Is psychology a science?........................................................................................................................32
Data analysis..............................................................................................................................................33
Levels of data.........................................................................................................................................33
Descriptive statistics..............................................................................................................................34
Inferential statistics...............................................................................................................................35
Probability and significance...............................................................................................................35
Choosing a statistical test..................................................................................................................36
The Sign test......................................................................................................................................37
Spearman’s rho..................................................................................................................................40
Chi-Squared test................................................................................................................................41
Mann-Whitney U test........................................................................................................................42
Wilcoxon signed ranks T test.............................................................................................................43
Pearson’s r.........................................................................................................................................45
T-tests................................................................................................................................................46
Summary of tests...............................................................................................................................46
Reporting psychological investigations......................................................................................................47
Extended RM questions.............................................................................................................................48
2
,Aims
Developed from theories
A general statement of what the researcher intends to investigate, the purpose of the study.
Hypothesis
A clear, precise, testable statement that is made at the start of a study and clearly states the
predicted relationship between variables to be investigated.
Directional hypothesis: makes clear the sort of difference that is anticipated between two
conditions or two groups of people.
o AKA ‘one-tailed hypothesis’
o Indicated by words such as: ‘more/less’, ‘higher/lower’, ‘faster/slower’
o Used when a theory or the findings of previous research suggest a particular outcome.
Non-directional hypothesis: simply states that there is a difference between conditions or
groups of people, but the nature of the difference is unspecified.
o AKA ‘two-tailed hypothesis’
o Indicated by phrases such as: ‘affected by’
o Used when there is no theory/previous research or when findings from earlier studies
are contradictory.
Null hypothesis: states that there is no difference, correlation or association between variables
being studied.
Variables
Independent variables (IVs): some aspect of the experimental situation that is manipulated by
the researcher – or changes naturally – so the effect on the DV can be measured.
Dependent variables (DVs): the variable that is measured by the researcher.
o Any effect on the DV should be caused by the change in the IV.
Control variables: any factor that is controlled or held constant during an experiment.
o e.g., light, temperature
Extraneous variables (EVs): any variable other than the IV that may affect the DV if it is not
controlled.
o Do not vary systematically with the IV.
o Researchers should, where possible, name these at the start of a study and attempt to
minimise their influence.
o They will not confound the findings of the study, but instead make it harder to detect a
result.
o e.g., age of participants, the lighting in the lab, demand characteristics
3
, Confounding variables: any variable that varies systematically with the IV, preventing us from
telling if any change in the DV is due to the IV or the confounding variable.
o e.g., in a study investigating the effects of caffeine on chattiness, the first half of the
participants to arrive are used for the condition with caffeine and the last half for the
control condition.
The first half who arrive are those who live closer and therefore got more sleep.
The second half arrived later due to having to get up earlier and travel further.
The confounding variable is therefore the amount of sleep.
The first half saw a celebrity outside their school. This resulted in a delay before
further participants arrived, and by then the excitement had died down. The
confounding variable is therefore the level of excitement.
Operationalisation of variables: clearly defining variables in terms of how they can be measured
o This makes it easier for the experiment to be replicated, reduces subjectivity and
increases the reliability of the study.
o e.g., the group that drinks caffeine will be chattier than the group that drinks water -->
after drinking 300ml of black coffee, participants say more words in five minutes than
participants who drink 300ml of water.
Research issues
Demand characteristics
o A participant changing their behaviour within the research situation based on
knowledge of/guesses at the investigation’s aim.
o They may act in a way that they think is expected and over-perform to please the
experimenter or may deliberately underperform to sabotage the results of the study.
Either way, participant behaviour is no longer natural.
Investigator effects
o Any effect of the investigator’s behaviour (conscious or unconscious) on the research
outcome (DV). This includes everything from the design of the study to the selection
of/interaction with participants during the research process.
o An example of this could be leading questions (looked at in the memory topic, in
relation to eyewitness testimony).
Controlling research issues
Random allocation
o An attempt to control for participant variables in an independent groups design which
ensures that each participant has the same chance of being in one condition as any
other.
o Participants are randomly distributed to the different experimental conditions;
therefore, participant characteristics are hypothetically evenly distributed across the
conditions of the experiment.
4
Research methods counts towards at least 25-30% of all marks.
Contents
Aims.............................................................................................................................................................3
Hypothesis...................................................................................................................................................3
Variables......................................................................................................................................................3
Research issues............................................................................................................................................4
Controlling research issues......................................................................................................................4
Experimental method..................................................................................................................................5
Types of experiment................................................................................................................................5
Experimental designs...............................................................................................................................6
Sampling......................................................................................................................................................7
Ethics...........................................................................................................................................................9
Pilot studies...............................................................................................................................................10
Observational techniques..........................................................................................................................10
Types of observation.............................................................................................................................10
Observational design.............................................................................................................................11
Behavioural categories......................................................................................................................11
Ways of recording data......................................................................................................................12
Sampling methods.............................................................................................................................12
Self-report techniques...............................................................................................................................12
Questionnaire........................................................................................................................................12
Interview................................................................................................................................................14
Designing interviews..........................................................................................................................15
Common errors in question design........................................................................................................16
Correlations...............................................................................................................................................16
Types of data.............................................................................................................................................18
Primary data..........................................................................................................................................18
Secondary data......................................................................................................................................19
Meta analysis.........................................................................................................................................19
Qualitative data.....................................................................................................................................19
Quantitative data...................................................................................................................................20
1
, Presentation of quantitative data......................................................................................................20
Distributions......................................................................................................................................21
Mathematical content...............................................................................................................................22
Peer review................................................................................................................................................23
Implications of psychological research for the economy...........................................................................24
Case studies...............................................................................................................................................25
Content analysis........................................................................................................................................26
Reliability...................................................................................................................................................27
Assessing reliability................................................................................................................................28
Improving reliability...............................................................................................................................28
Validity.......................................................................................................................................................29
Assessing validity...................................................................................................................................29
Improving validity..................................................................................................................................29
Features of science....................................................................................................................................30
Is psychology a science?........................................................................................................................32
Data analysis..............................................................................................................................................33
Levels of data.........................................................................................................................................33
Descriptive statistics..............................................................................................................................34
Inferential statistics...............................................................................................................................35
Probability and significance...............................................................................................................35
Choosing a statistical test..................................................................................................................36
The Sign test......................................................................................................................................37
Spearman’s rho..................................................................................................................................40
Chi-Squared test................................................................................................................................41
Mann-Whitney U test........................................................................................................................42
Wilcoxon signed ranks T test.............................................................................................................43
Pearson’s r.........................................................................................................................................45
T-tests................................................................................................................................................46
Summary of tests...............................................................................................................................46
Reporting psychological investigations......................................................................................................47
Extended RM questions.............................................................................................................................48
2
,Aims
Developed from theories
A general statement of what the researcher intends to investigate, the purpose of the study.
Hypothesis
A clear, precise, testable statement that is made at the start of a study and clearly states the
predicted relationship between variables to be investigated.
Directional hypothesis: makes clear the sort of difference that is anticipated between two
conditions or two groups of people.
o AKA ‘one-tailed hypothesis’
o Indicated by words such as: ‘more/less’, ‘higher/lower’, ‘faster/slower’
o Used when a theory or the findings of previous research suggest a particular outcome.
Non-directional hypothesis: simply states that there is a difference between conditions or
groups of people, but the nature of the difference is unspecified.
o AKA ‘two-tailed hypothesis’
o Indicated by phrases such as: ‘affected by’
o Used when there is no theory/previous research or when findings from earlier studies
are contradictory.
Null hypothesis: states that there is no difference, correlation or association between variables
being studied.
Variables
Independent variables (IVs): some aspect of the experimental situation that is manipulated by
the researcher – or changes naturally – so the effect on the DV can be measured.
Dependent variables (DVs): the variable that is measured by the researcher.
o Any effect on the DV should be caused by the change in the IV.
Control variables: any factor that is controlled or held constant during an experiment.
o e.g., light, temperature
Extraneous variables (EVs): any variable other than the IV that may affect the DV if it is not
controlled.
o Do not vary systematically with the IV.
o Researchers should, where possible, name these at the start of a study and attempt to
minimise their influence.
o They will not confound the findings of the study, but instead make it harder to detect a
result.
o e.g., age of participants, the lighting in the lab, demand characteristics
3
, Confounding variables: any variable that varies systematically with the IV, preventing us from
telling if any change in the DV is due to the IV or the confounding variable.
o e.g., in a study investigating the effects of caffeine on chattiness, the first half of the
participants to arrive are used for the condition with caffeine and the last half for the
control condition.
The first half who arrive are those who live closer and therefore got more sleep.
The second half arrived later due to having to get up earlier and travel further.
The confounding variable is therefore the amount of sleep.
The first half saw a celebrity outside their school. This resulted in a delay before
further participants arrived, and by then the excitement had died down. The
confounding variable is therefore the level of excitement.
Operationalisation of variables: clearly defining variables in terms of how they can be measured
o This makes it easier for the experiment to be replicated, reduces subjectivity and
increases the reliability of the study.
o e.g., the group that drinks caffeine will be chattier than the group that drinks water -->
after drinking 300ml of black coffee, participants say more words in five minutes than
participants who drink 300ml of water.
Research issues
Demand characteristics
o A participant changing their behaviour within the research situation based on
knowledge of/guesses at the investigation’s aim.
o They may act in a way that they think is expected and over-perform to please the
experimenter or may deliberately underperform to sabotage the results of the study.
Either way, participant behaviour is no longer natural.
Investigator effects
o Any effect of the investigator’s behaviour (conscious or unconscious) on the research
outcome (DV). This includes everything from the design of the study to the selection
of/interaction with participants during the research process.
o An example of this could be leading questions (looked at in the memory topic, in
relation to eyewitness testimony).
Controlling research issues
Random allocation
o An attempt to control for participant variables in an independent groups design which
ensures that each participant has the same chance of being in one condition as any
other.
o Participants are randomly distributed to the different experimental conditions;
therefore, participant characteristics are hypothetically evenly distributed across the
conditions of the experiment.
4
