research methods Flashcards
aims meaning
the aims of a study is what the purpose is of a piece of research. for example, to test if age affects memory
hypothesis definition
the prediction of what the research will be
alternative hypothesis meaning
a testable statement which predicts how one variable will affect another. it is a statement which predicts a difference between conditions in an experiment or a correlation between two variables
null hypothesis
states that there is no relationship between the two variables being studied. There will be no changes in the dependent variable due to manipulation of the independent variable. It states results are due to chance and are not significant in terms of supporting the idea of being investigated
non directional hypothesis
a two tailed hypothesis predicts that the independent variable will have an effect on the dependent variable, but the direction of the effect is not specified. it just states that there will be a difference.
eg. there will be a difference in how many numbers are correctly recalled by children and adults
directional hypothesis
a one tailed hypothesis predicts the nature of the effect of the independent variable on the dependent variable. it predicts in which direction the change will take place.
eg. adults will correctly recall more words than children
random sampling
each member of the target population has an equal chance of being selected. for example using random number generator, or picking names out of a hat
pros of random sampling
there is no bias
simple
cons of random sampling
large random sampling may be impractical, complete list of the population may be unbelievable
systematic sampling
a participant is selected in a systematic way, for example, selecting every 10th person from the electoral roll. this is decided through a sampling frame, where a list of the target population is put in order
pro of systematic sampling
lower probability of contaminating data
cons of systematic samping
under representation of particular patterns, grater risk of data manipulation
stratified sampling
the total population is divided into smaller groups or strata to complete the sampling process
pros of stratified sampling
you obtain reasonable precise estimates for all subgroups related to your research questions
cons of stratified sampling
the selection of appropriate strata for a sample may be difficult
opportunity sampling
participants are selected from whoever is most easily available. For example, standing in the street one afternoon and approaching passers-by to see if they want to take part
pros of opportunity sampling
quick way and easy of choosing participants
cons of opportunity sampling
may not provide a representative sample, could be biased
volunteer sampling
participants put themselves forward to take part in a study. For example, a newspaper or internet advert is placed asking for volunteers, and people respond agreeing to take part
pros of volunteer sampling
not time consuming, easily minimal effort is required
cons of volunteer sampling
volunteer bias, cannot be generalised
extraneous variables
an unwanted factors in a study that, if not accounted for, could negatively affect the data subsequently collected. such factors potentially prevent researchers from finding a direct casual effect between the manipulated independent variables and measured dependent variables set out in an investigation