psychology research methods

what are lab experiments?

experiments that are conducted in a highly controlled environment

this doesn’t have to be a lab, it can be a classroom where conditions are well-controlled

what are strengths of a lab experiment?

• high control over extraneous variables, so can ensure that the DV is the result of the IV being manipulated so high internal validity

• replicable because of high level of control which is vital to check if the experiment is valid

what are the limitations of lab experiment?

• lack of generalisability because the artificial conditions so has low external validity

• demand characteristics because participants often know they are being tested in a lab

• not representative of real life experiences so low mundane realism

what are field experiments?

experiments when the IV is manipulated by the researcher in a more natural, everyday environment

what are some strengths of a field experiment?

• higher mundane realism as the environment is more natural

• high external validity because more authentic, valid behaviour is studied as pp may be unaware of being studied

what are some limitations of a field experiment?

• loss of control over extraneous variables

• cause and effect is harder to establish 

• lack of replicability

• ethical issues because of lack of consent, invasion to privacy

what are natural experiments?

experiments when the researcher takes advantage of pre-existing independent variables

IV is naturally occurring and not necessarily the setting

what are some strengths of natural experiments?

• provides opportunities for research which is otherwise unethical

• high external validity as involved in real-life issues

what are some limitations of natural experiments?

• naturally occurring events happen very rarely

• pp may not be randomly allocated to experiments (only applies when there is an independent groups design)

what are quasi experiments?

IV based on an existing difference between people, no one has manipulated this

eg age or gender

what are strengths of quasi experiments? 

controlled so same strengths as a lab

• high control over extraneous variables, so can ensure that the DV is the result of the IV being manipulated so high internal validity

• replicable because of high level of control which is vital to check if the experiment is valid

what are limitations of quasi experiments?

• confounding variables as cannot randomly allocate pp

which experiments are not a ‘true’ experiment?

natural and quasi

why are some experiments not classified as ‘true’?

cannot be manipulated by the researcher

what is independent group experimental design?

sample is split into two groups 1st group participates in condition A and 2nd group participates in condition B

what is repeated measures experimental design?

sample takes part in both condition A and B of experiments

what is matched pairs experimental design?

pp are paired with other pp on a variable or variables related to study

each person from the pair goes to a different experimental condition

what is a limitation to independent groups experimental design? And how can it be overcome?

• individual differences

random allocation

what is are limitations to repeated measures experimental designs? And how can it be overcome?

• order effects

• demand characteristics

counterbalancing

what is limitation of matched pairs experimental design? And how can it be overcome?

• time consuming

• expensive

data bases

what is the strength of independent group experimental design?

• no order effects

what is the strength of repeated measures experimental design?

• pp variables are controlled

• less pp needed

what are the nuisance variables in research?

• extraneous variables

• confounding variables

what are extraneous variables?

all variables which are not the independent variable but could affect the results (DV) of the experiment. It should be controlled where possible

what are confounding variables?

variables that have affected the results (DV) apart from the IV

it could be an extraneous variables that is uncontrolled

what is the meaning of validity?

extent to which a research technique actually measures the behaviour it is claimed to measure

what is internal validity?

• validity inside the study

• does IV really cause the change on the DV?

• Did the researcher test what he set out to test?

what is external validity?

ability to distinguish results outside of research situations to..

• different places/ settings ecological validity

• different people/populations population validity

• different times temporal validity

affected by internal validity, as cannot generalise results of study if it has low internal validity

what are the types of researcher bias in relation to confounding variables?

• investigator effects

• experimenter expectancy effects

what is investigator effects?

refers to unwanted influence of the researcher on the research outcome

e.g

• failing to follow standardised procedures

• not recording events properly

what is experimenter expectancy effects?

any expectations of the researcher may influence the outcome by affecting the pp 

e.g

• smiling

• nodding of head

• tone of voice

what are the types of participants reactivity in relation to confounding variables?

• demand characteristics

• evaluation apprehension /social desirability bias

how is investigator effects and experimenter expectancy overcome by?

• double blind procedure

• standardised instructions and procedures

• high control of research situation

• use of the same researcher

• avoid ‘cues’ and ‘expectations’ being conveyed to pps

how is demand characteristics overcome by?

• single blind procedure

• tell pp another aim instead of real one

how is evaluation apprehension/ social desirability  overcome by?

treat all pp in the same way, make it equally clear that their behaviour is of interest

what does face internal validity mean?

does the test look like it measures what it says it measures (on the surface)

e.g

ask other people

what does construct internal validity mean?

whether a measure successfully measures the concept it is supposed to 

e.g

attachment type

what does concurrent internal validity mean?

assesses validity by comparing it to an established test for the same measure

e.g

IQ or Stress test

what does predictive internal validity mean?

how well does the test predict future behaviour

what are the two types of external validity?

• population validity

• ecological validity

what are some other threats to generalisability/validity?

• androcentrism (if it only applies to men and therefore it has gender bias)

• ethnocentrism (if the study was only conducted in one culture)

• gynocentrism (if it only applies to women)

what is the an aim?

a general statements of why a study is taking place

what is a hypothesis?

precise, testable statement giving a research prediction and stating the variables being investigated

what is experimental/alternative hypothesis?

predicts that differences in the DV will be beyond the boundaries of chance and will be caused by the manipulation of the IV

what is correlational hypothesis?

predicts a relationship between two variables

what is the null hypothesis?

the hypothesis of no difference. It predicts the the IV will not affect the DV

what is one tailed/ directional?

predicts there will be a difference caused by the IV and the direction of the results

what is two tailed/ non directional?

predicts there will be a difference is the results but does not predict which direction

what are all the sampling techniques?

• random

• systematic

• stratified

• opportunity

• volunteer

what is a sample?

a group of people that take part in research

they are selected from, and should be representative of the target population

what is sampling?

a method used to select people from a population, ideally smaller, more representative group, the purpose being to create results which can be generalised beyond the participants of the study

what is target population?

group of people from whom the sample is drawn

what is opportunity sampling?

taking the sample from people who are available at the time the study is carried out and fit the criteria

what is random sampling?

every member of the population has an equal chance of being chosen

what is volunteer samplying?

self selected sample consists of pp becoming in the study because they volunteer when asked or in response to an advert

what is stratified sampling?

classifying the populations into categories and then choosing a sample from each category in the same proportion as they are in the population

what is systematic sampling?

choose every nth person to be selected to participate in your sample

what are the limitations of opportunity sampling?

• not representative of target population

what are the strengths of opportunity sampling?

• easy,quick

what are the limitations of random sampling?

• time consuming

• small minority group within your target population and may distort our results

what are the strengths of random sampling?

• more representative as each member has an equal chance of being selected

what is limitations of stratified sampling?

• time consuming

• care must be taken to ensure each key characteristic present in population is selected across the strata or would be bias

what are the strengths of stratified sampling?

• more representative

what are the strengths of volunteer sampling?

• easy to do

• can achieve a large sample

what are the limitations of volunteer sampling?

• one type of person volunteers so not representative

what is limitation of systematic sampling?

• list assembled in a way that isn’t random so bias may be present

what is a strength of systematic sampling?

• meant to be representative

what are pilot studies?

small, trial versions of the proposed studies

why use pilot studies?

• test their effectiveness

• make improvements

• identify potential issues

what can be tested in a pilot study?

anything

what does reliability refer to?

consistency

what is internal reliability?

internal consistency of a measure, such as whether the different questions (known as items) in a questionnaire are all measuring the same construct

what is external reliability?

assesses consistency of a measure from one use to another

what is the split half method?

measures to the extent to which all parts of the test contribute equally to what is being measured. This is done by comparing the results of one half of the test to the other half to establish internal validity

what is the test-retest method?

measures external validity by giving the same pp the same test on two occasions. If the same results are obtained, reliability has been established

what is the inter-observer/ inter-rater reliability?

two or more researchers observe and rate behaviour independently. If their observations are similar this helps establish external validity

what is the measures of dispersion?

• the range

• standard deviation

what is the measures of standard deviation?

provides measures off the variability of the data

what are the three levels of data?

• nominal

• ordinal

• interval

what is nominal data?

• named categories

• no true mathematical value

what is ordinal data?

• ordered data

• normally a scale

what is interval data?

• eg temp for ‘ter’

• true mathematical value

what are the strengths of the mode?

• easy to calculate

• in some data methods its the only possible method

what are limitations of the mode?

• crude measurement as doesn’t take in account the median or the mean so not representative of the whole data

• some data sets may have two modes (bi-modal) or no mode if all scores are different

what are strengths of the median?

• extreme scores do not affect it

• easily identifiable 

what are some limitations of the median?

• less sensitive than the mean as it does not include the calculation of all scores

what are strengths of the mean?

• most sensitive measurement as it includes all scores in data set so is more representative

what are limitations of the mean?

• easily distorted by extreme values

what is the strength of the range?

• quick and easy to calculate

what is limitations of the range?

• only takes in account 2 most extreme scores

• unfair representative of spread of all scores

• less precise dispersion measurement

what are strengths of standard deviation (SD)?

• much more precise measure of dispersion than range 

It takes into account a calculation of all the scores

what is the limitation of standard deviation (SD)?

• like the mean, it can be distorted by freak values

what are all the ways of representing data?

• summary tables and summary paragraphs

• bar charts

• scattergraphs

what are the types of distribution?

• normal

• positively skewed

• negatively skewed

what are the characteristics of a positively skewed graph?

• mode is the highest point

• median is second highest on the right

• median is third highest on the furthest right

what are the characteristics of a negatively skewed graph?

• mode is the highest point

• median is second highest on the left

• mode is third highest on the furthest left

what is discrete data?

when data can be put into categories