Experiments unit 1 Flashcards
advantages of lab experiments
you can control what you are measuring
easy to replicate
disadvantages of lab experiments
low ecological validity
advantages of field experiments
ecologically valid
replicates what you do everyday
disadvantages of field experiments
more difficult to control
extraneous variables
advantages of quasi experiments
can study variables which are impossible to replicate
disadvantages of quasi experiments
can’t control it
difficult to replicate
repeated measure design
this involves using the same people in each condition
independant measure design
this involves using different people in each condition
matched participants design
This involves using different people in each condition but attempt is made to make the participants as similar as possible on certain characteristics (I need that may influence the findings) this is done by testing the individuals on key characteristics pairing them based on similar scores and then placing one member of each pair and each group.
advantages of repeated measure design
participants won’t have different characteristics
disadvantage of repeated measure design
order effects- experiments results may be influenced by the repetition
higher chance of demand characteristics
advantages of independent measure design
no order effects
less chance of demand characteristics
disadvantages of independent measure design
participants will have different characteristics, backgrounds, strengths/weaknesses
advantages of matched participants design
less participant variables
less demand characteristics
no order effects
disadvantages of matched participant design
time consuming
lots of effort to match people
participant variables
age, intelligence, motivation, skill, experience, gender
situational variables
order effects- if doing the same activity twice, participants may be better the second time because of practise or worse because of boredom
environmental factors- such as time of day, temperature and noise
demand characteristics- these are cues in an experiment that communicate to participants what is expected of them and which may unconsciously affect the behaviour of participants
alternative hypothesis
this predicts how one variable (the IV) is likely to effect another variable (the DV)
an alternative hypothesis predicts that the IV will effect the DV
null hypothesis
this predicts that the IV will not have an effect on the DV. the null hypothesis predicts that any difference seen will be due to chance factors rather than the independent variable
It predicts that there will be no effect
Two tailed
this predicts that the IV will have significant effect on the DV (ie there will be a significant difference in the results from the different conditions of the experiment) but it does not protect the direction this affect all going with our two tailed cat we cannot predict which direction he will go in.
one tailed
This predicts not only that but IV will have a significant effect on the DV but also that direction this effect will go in (e.g. the condition of the experiment in which more of something will be seen) without one told Carr we can put it the direction he will go in.
operationalise
Refers to the process of making variables physically measurable or testable.
target population
the group of people the researcher is interested in studying
sampling methods
the different ways in which researchers can obtain a sample of people from within the target population to take part in their study
sample
the actual group of participants used in the research
self selecting
recruting people who volunteer to participate in the study
opportunity sampling
researcger selecting anyone who is available and willing to take part in the study
random sampling
participants randomly selected by researchers- each person is equally likely to be chosen
snowball
participantsare asked to help recruit othr participants eg asking your friends
