experimental design Flashcards
what is data?
information/measurements gathered during the course of a study
what is data analysis?
interpretation of data allows the research psychologist to draw conclusions about the event under study
what is qualitative data
language-based data collected through interviews, open questions and content analysis. Focus is on non-numerical data e.g. verbal reports
it explores how an individual subjectively perceives and gives meaning to their social reality e.g. through observations and case studies
strengths of qualitative data
- allows researchers to develop insights into nature of subjective experiences, opinions and feelings
- get a real feel for emotions, in pps own languages
- subjective input from pp
- meanings emerge from words
weaknesses of qualitative data
- time consuming to analyse
- subjective interpretations by researchers, researcher bias in interpretation of themes and content
- not often replicable
what is quantitative data?
this data involves the process of objectively collecting and analysing numerical data to describe, predict, or control variables of interest
the focus is on numerical data, such as experiments and some questionnaires, surveys
strengths of quantitative data
- gives objective numerical data
- easy to compare findings and draw conclusions e.g. cause and effect in well controlled experiments
- attempts to generalise to wider populations
- can predict trends and patterns
- easily presented in graphical form
- often replication is possible
weaknesses of quantitative data
- fails to capture totality of human experience and essence of what it is to be human
- methods limit possible ways in which a research participant can react
- no real detail or personal insight
- often data is artificial settings
how is an experiment conducted
- causal observation about one feature of the world e.g. people imitate violence on TV
- those observations form a theory
- theories will produce a number of further expectations which is stated as a hypothesis
- the experiment sets out to support/challenge this hypothesis and make a causal link
what is triangulation?
a combination of both qualitative and quantitative studies
what is an experimental degin?
the way in which participants are allocated to conditions
what is the independent variable?
variable that is changed
what is the dependent variable
the variable that is measured
what is the controlled variable
the one that stays the same
what are extraneous variables?
variables that have the potential to affect the results e.g. time of day/mood
what are confounding variables?
extraneous variables that are uncontrolled and so affect results
what is independent groups design?
- different groups in each condition
- pps likely to be randomly allocated to each condition
e. g. Baddeley
advantages of independent groups
- no order effects
- demand characteristics less likely
- pps not lost between trials
- saves time and effort
- can be used when measures inappropriate (e.g. looking at gender differences)
disadvantages of independent groups
- may be individual differences between pps
- you need more participants to get the same amount of data which can be costly
what are order effects
pps performance in condition may be affected by the order in which they are performed e.g. performance improves
what is a matched pairs design
- each pp only in one condition
- pps in two groups are matched on a relevant condition that you want to measure (intelligence, gender, age)
- different pps in each condition matched on important variables
advantages of matched pairs
no order effects - different pps in each condition
controls for some individual differences
less likely to show demand characteristics
disadvantages of matched pairs condition
difficult to do time consuming difficult to find pps who match need a large group of pps identical twins best - many differences taken care of
what is a repeated measures design?
each participant appears in both conditions
e.g. all pps asked to do without music then with
advantages of repeated measures
individual differences taken care of - tested against themselves
requires fewer pps but gather more data
disadvantages of repeated measures design
- demand characteristics
- can’t be used in studies where pps in one condition has large effects on response in the other or where pps are likely to guess the purpose of the study
- order effects - can be reduced by counterbalancing
what is counterbalancing
involves ensuring that each condition is equally likely to be first or second
one half in AB condition
one half in BA condition
what is a control group?
where one group is used to provide baseline info
- one group receives the experimental treatment (manipulation of IV)
- the control group acts as a comparison to the experimental group to study the effects
