samples and designs Flashcards
what is central theorem
the means of random samples from any distribution will themselves have normal distribution
what is bad about self selection
it is bias
what are the non-probability sampling methods
opportunity sampling, snowballing, purposive, quota
what is snowballing sampling
it is when you find participants and tell them to find other people for the study
what is purposive sampling
when you get a sample of specific people
what is quota sampling
specific pool of people, nurses, doctors etc.
what are the probability sampling methods
stratified random sampling, simple random sampling, cluster sampling, systematic sampling
what is bad about non-probability sampling
prone to bias
what is stratified sampling
getting a specific sample of people
what are cluster samples
get a cluster of participants and then chose between that cluster of people
what is systematic sampling
every 10th person gets to take part in the study
what are the two survey designs
cross sectional and longitudinal
what is a cross-section survey
when the survey is done by different people but the same time every year
what is age confounding
when the age of someones effects the validity of the data
