test 2 Flashcards
goal of sampling
obtain a sample that is representative of the population
random sampling
every member has an equal chance of selection and a tool is used to randomly select individuals
random sampling can lead to
over/under representation of subgroups
convenience sampling
recruits participants from the accessible population (individuals who are readily available or easier to access)
volunteer samples
participants choose to participate and usually respond to recruitment flyers/letters or through online recruitment companies
problems with volunteer samples
- they may have bias (certain individuals are more likely to agree to participate)
- possibility of bots plus privacy and anonymity concerns
issues with convenience sampling
- issues with generalizability
- sample must be representative in order to infer findings to population or another sample
- replication can increase external validity
random assignment uses
similar procedures to random sampling but applied to enrolled participants to determine which study group they belong to
random assignment
the process of deciding which group individuals will be in (happens after sampling has occurred)
confirmation bias
tendency to accept confirming and downplay contrary evidence
illusory correlation
seeing patterns/correlation where there is none
probability in statistics
we are interested in expected relative-frequency probability - likelihood of occurrence based on the outcome of many, many trials
relative probability
likelihood is related to the overall number of trials
probability is the
proportion that we anticipate to see in the long run: successes/ total number of trials
percentage is
simply probability or proportion multiplied by 100 (different expression of same value ex: 0.50 vs 50%)
