research methods - em1 Flashcards
what do all experiments have?
an independent variable, a dependent variable, conditions
define variable
things that can be changed or altered
define independent variable
the variable that is manipulated to observe its effects
define dependent variable
the variable that is measured and affected by the IV
define operationalisation
clearly specifying/turning abstract concepts into measurable observations
define hypothesis
a testable statement about the relationship between the variables that are going to be studied
what is a directional/one-tailed hypothesis?-
states the direction of the difference/relationship between variables, used when there is previous research to suggest a direction
define non-directional/two-tailed hypothesis
predicts that a difference will exist between variables without predicting the exact difference
define target population
the group that the researcher draws the sample from & attempt to generalise the findings to
define sampling bias
when a sample is mainly made up of one particular type of person
define sample
a group of people that are drawn from the target population to take part in an experiment
define representative sample
a sample that closely matches the target population
define generalise
applying results to a wider population beyond the research participants
what are the methods of random sampling?
-pull names from a hat
-random name generator
advantages of random sampling
-everyone in the population has an equal chance of being chosen
-free from researcher bias (researcher has no input into who is chosen)
↳ sample is representative & generalisable
disadvantages of random sampling
-it’s time consuming & dificult to ensure that everyone in the population has an equal chance of being chosen
-people who are picked may be unwilling to take part
what is systematic sampling?
when a predetermined system is used to select participants
(eg: every nth person)
strengths of systematic sampling
-no researcher bias (researcher has no input into who’s chosen)
weaknesses of systematic sampling
-sample may not be representative
↳ each participant may have similar characteristics
what is stratified sampling?
-strata are identified
-subgroups are represented in proportion their occurrence within the population
strengths of stratified sampling
-this is the only sampling technique that will give a fully representative sample
↳ results can be generalised
weaknesses of stratified sampling
-difficult to identify each strata in the target population
what is opportunity sampling?
anyone who’s willing and available to take part in the study at the time is chosen
strengths of opportunity sampling
-quick and easy
-no researcher bias
weaknesses of opportunity sampling
-not representative
what is volunteer sampling?
ask people to take part/participants respond to an advert