experiments Flashcards
types of experiments
- laboratory
- field
- quasi
laboratory
the independent variable is manipulated by the researcher and the experiment is carried out in a lab or other highly controlled setting away from the participants normal environment.
field experiment
the independent variable is manipulated by the researcher but the experiment is carried out in the participants normal environment
quasi experiment
the independent variable is naturally occurring and is not manipulated by the researcher (i.e. cloudy conditions vs sunny conditions).
advantages of lab experiments
- controlled settings reduces the effects of extraneous variables
- increases internal reliability as the procedure would be standardised and can be replicable many times
disadvantages of lab experiments
- low ecological validity as due to the unnatural behaviours, it cannot be generalisable to real life settings or scenarios
- more effort, time and money in order to conduct research
advantages of field experiments
- controlled settings
- high ecological validity as it can be generalised to a real life scenario
- produces more natural behaviour
- high internal validity
- less effort to set up and conduct
disadvantages of field experiments
- demand characteristics where participants will know that they are being observed and will alter and adapt their behaviour in terms of what the study is about
- higher chance of extraneous variables which would alter and influence the results
- low internal validity as participants may have different experiences
advantages of quasi experiment
- high ecological validity as the iv is not manipulated and can generalise to real life scenarios
- helps us study variables that we cannot manipulate
disadvantages of quasi experiment
- difficult to conduct in some situations
- cannot control some participants to variables that may influence the results
experimental designs
- repeated measures
- independent
- matched participants
repeated measures
using the same people in each condition
independent measures
using different people in each condition
matched participants
using different people in each condition but an attempt is made to make the participants as similar as possible on certain key characteristics. this is one by testing the individual on key characteristics, pairing them based on similar scores and then placing one member of each pair into each group
advantages of repeated measures
- removes the effects of any participant variables on the cause and effects as participants take part in both conditions
- easier to obtain sample as fewer participants are needed overall
disadvantages of repeated measure designs
- demand characteristics as participants may try to identify what the experiment is about by predicting and altering their behaviour
- order effects may influence results unless counter-balanced
advantages of independent measure design
- reduced demand characteristics as the participants in each condition are unaware of the other
- ## no order effects as participants only take part in one condition.
disadvantages of independent measure designs
- high levels of effort to collect more participants as you need different people
- findings may be influenced by participant variables
advantages of matched participant design
- reduced effects of participant variabes
- no order effects as different participants for each condition
- lower chance of demand characteristics as participants only do one condition
disadvantages of matched participants design
- more effort and time consuming to find sample
- cannot control all of the extraneous variables by perfectly matching participants
types of extraneous variables
- participant variable
- situational variable
participant variable
characteristics of the individual participant the may influence the results
i.e. age, intelligence, motivation, experience, gender
situational variable
any feature of the research situation which may influence a participants behaviour and therefore the results
i.e.
order effects.
environmental factors
demand characteristics
order effect
which is where if doing the same activity twice, participants may do better the second time because of practice or boredom.
environmental factors
the time of the day, temperature, noise
demand characteristics
cues in an experiment that communicates the participant which may unconsciously affect the behaviour of participants
single blind
participants dont know the aim of the study
double blind
neither the participant or the researcher knows the aim of the study to reduce researcher effects and researcher bias
2 types of hypotheses
- alternative
- null
alternative
“there will be a significant difference in the number of balls successfully thrown into a bucket when completing a task infant of a noisy audience as opposed to a quiet audience”
- the iv is likely to affect the dv
null
” there will not be a significant difference in the number of balls successfully thrown into a bucket when completing a task infant of a noisy audience as opposed to a quiet audience; any difference will be due to chance factors”
- the iv does NOT have any effect on the dv, if there is it will be due to chance factors
direction of hypotheses
- one tailed
- two tailed
two tailed hypothesis
the iv will have a significant effect on the dv, but does not predict the direction the effect will go in.
one tailed
the iv will have a significant effect on the dv, also predicts the direction the effect will go
i.e. more/quicker/faster, slower/lower/less
sample and sampling methods
- target population
- sampling method
- sample
target population
the group of people the researcher is interested in studying
sampling method
the different ways in which researchers can obtain a sample of people from within a target population to take part in their study
sample
the actual group of participants used in the research
different sampling methods
- self selecting
- opportunity
- random
- snowball
self selecting
when people volunteer to take part in the study often through adverts, posters, leaflets which contains details about the research and contact details for participants who are willing to take part
opportunity
a sample of participants produced by selecting those who are already available at a given time and place selected by the researcher
random
each member of the population have an equal chance of being selected
snowball
when participants are asked to contact their friends and family to ask them to take part in their research
advantages of self selecting sample
- people are willing to take part
- easy to obtain participants
disadvantages of self selecting sample
- only certain types of people would take part
- unrepresentative
- expensive
- small sample size
advantages of opportunity sample
- cost effective
- time efficient
- easy to obtain
disadvantages of opportunity sample
- might not be a varied sample
- low diversity
- unrepresentative
- researcher biased
advantages of random sample
- everyone has an equal chance of being selected
- representative of a target population
disadvantages of random sample
- hard to ensure that all participants have an equal chance at being selected
- selected people may not be willing to take part
advantages of snowball ample
- easy to obtain sample
disadvantages of snowball sample
- can be bias
- time efficient
- low in variety
- participant variables
- not able to generalise sample as family and friends often have similar characteristics
types of data
- primary
- secondary
primary data
data that has been collected directly by the researcher
secondary data
information that someone else has collected and already exists
types of data
- qualitative
- quantitative
qualitative
data that consists of rich and detailed information which is either descriptions, words, meanings, pictures
quantitative
data that can be converted into numerical and statistical form
strengths of quantitative data
- provides data in statistical and numerical form
- easy to spot trends and patterns which can be analysed and compared
- no personal bias when interpreting them
weakness of quantitative data
- cannot understand why the data is the way it is
- misleading results
- doesn’t capture the complexity, diversity and richness detail of the study
strengths of qualitative data
- provides rich and detailed information about the data
- captures the meaning, motivations and complexity of the study
- multiple methods for gathering data on sensitive topics
weakness of qualitative data
- difficult to maintain
- time consuming
- the researcher has to be present when getting answers which may affect the answers of participant
