Research methods (topic 11) Flashcards
what is an independent variable
a variable in an experiment that is manipulated and is assumed to have a direct effect on the dependent variable
what is a dependent variable
a variable in an experiment that is being measured and is dependent on the independent vaiable
ecological validity
the degree to which an investigation represents real life experiences
what is an extraneous variable
–factors in a study that could interfere with the IV and DV and that could affect the results of the study (e.g., noise)
–may affect the validity
–of these factors are not controlled they become cofounding variables
extraneous variables
situational factors
–aspects of the environment that can affect the ppt’s bahviour
–how the study is conducted could also introduce situational variables, e.g., ppt may improve if they repeat the study. this is called the order effect
extraneous variables
participant variables
–refers to the ways in which each ppt varies from the other and how this could effect the results e.g., mood, intelligence, etc.
extraneous variables
investigator effect
–when the experimenter unconsciously conveys to ppt how they should behave - experimenter bias.
extraneous variables
demand characteristics
–the clues in an experiment which convey to the ppt the purpose of research which may lead to the ppt altering their behaviour.
how to control situational variables
–standardised procedure:
enduring that the situation and procedure are exactly the same for each ppt.
–counterbalancing:
giving half of the ppt condition ‘A’ and the condition ‘B’ and giving the other half of the ppts condition ‘B’ and then condition ‘A’
–randomisation:
assigning the ppts randomly to avoid bias
how to control ppt variables
–random allocation:
randomly allocating ppt to the condition of the study to prevent only a certain type of person being in one condition
demand characteristics
the clues in an experiment that lead the ppt to think they know the aims of the study
how to control demand characteristics
–single-blind technique:
when the information of the study is withheld from the ppt
–double-blind technique:
when both of the ppt and researcher are unaware of the aims of the study
what is a null hypothesis
–hypothesis that states that there is no or very little effect
–states that there is no relationship between the variables
–any difference is due to chance
what is an alternative hypothesis
–states that there is a relationship between two variables
–not due to chance
what is non-directional hypothesis
–it is used when a theory cannot make a clear prediction and the evidence is mixed
–there will be a difference in how many numbers are recalled correctly by adults and children
what is a directional hypothesis
–it issued when a theory makes a clear claim, so the direction of the hypothesis can be predicted
–e.g., adults will correctly recall more words than children
random sampling
–when everyone in the entire target population has an equal chance of being selected
–requires a way of naming or numbering the target population then using a raffle method in choosing
random sampling
strengths
–provides the best chance of an unbiased representative sample
–helps control ppt variables (demand characteristics)
random sampling
weakness
–time-consuming
–some people may refuse to take part in the study
volunteer smapling
–putting together a sample of ppt who have volunteered to take part in a research
–ads can be used
volunteer sampling
strength
–easy to arrange
–most ethical option, as they will apply if they want to
volunteer sampling
weakness
–not representative of the target population (compared to stratified and random sampling)
–not everyone in the target population will apply
–biased sample- volunteers can be considered as having a particular personality type
stratified sampling
–the researcher identifies the different types of people that make up the target population and works out the proportions of each type of people in it
–once different types of people are identified, a random sample will be selected from each group so that they are represented proportionately
stratified sampling
strength
–deliberate effort to ensure that the sample is completely representative
stratified sampling
weaknesses
–time consuming (subgroups need to be identified and calculations made)
–people can refuse to take part
opportunity sampling
–based on convenience
–an opportunity sample is obtained by asking the members if they would take part in the study.
opportunity sampling
strengths
–quick and convenient method
–economical
opportunity sampling
weaknesses
–can lead to biased sample
–not representative sample as the researcher is likely to choose people who are ‘helpful’
–findings are likely not generalisable
independent measures design
–different ppts are used in each condition of the IV
–each condition of the experiment includes a different group of ppts
–ppt cannot be in both conditions
–can be done by random allocation to ensure that each ppt has an equal chance of being assigned to one groups or the other
independent measures design
strengths
–ppt won’t guess the aims of the study. prevents demand characteristics
–there are no order effects as ppts only take part in 1 condition. this means participant variables. (mood)