Sampling and Probability Flashcards
chapter 5
random sample
every member of the population has an equal chance of being sampled
convenience sample
sample is made from subjects who are easily available
generalizability is also called…
external validity
volunteer sample is also called…
self-selected sample
crowdsourcing
type of volunteer; researchers solicit input from a very large sample, usually online
random assignment
every subject in the study has the same chance of being assigned to a condition
confirmation bias
tendency to look at evidence in a selected way that confirms what we already believe
illusory correlation
seeing an association between two variables when there is no correlation
personal probability
or subjective probability; own uninformed judgment about likelihood of an occurrence
expected relative-frequency probability
likelihood of an event occurring based on actual outcomes of many many trials
formula for probability
successes divided by number of trials
null hypothesis
proposes that there is no effect in the population
what can happen to the null hypothesis after testing for an effect?
we can reject or fail to reject the null hypothesis.
Type I error
we reject the null hypothesis when we shouldn’t have (false positive)
Type II error
we fail to reject the null hypothesis when we should have (false negative)
