week 2 Flashcards
What is population
: the group we are interested in knowing more about
What is sample
the group of individuals chosen from the population to represent it in a research study
What is a representative sample
the sample contains sub-groups of people in direct proportion to their prevalence in the general population
What do we seek with a sample
External validity so that research can be generalized to the real world
Does sample size matter
Large samples are good but they are not always representative of the population
What is sampling bias
systematic tendency towards over or under-representation of some categories in a sample
What is a biased sample
A sample in which members of a sub-group of the larger population are over or under-represented
What is standard error
measures how well the mean of a particular sample represents the mean of the population
What is probability sampling
there is a specific/known probability of each member of the population being sampled
What is non-probability sampling
there is not a specific and known probability of each member of the population being sampled
What types of probability sampling
Simple random sampling
systematic random sampling
stratified sampling
cluster sample
What is simple random sampling
sample is chosen randomly from the population, so everyone has an equal chance of being selected. Reduces sampling error
What is systematic random sampling
method that requires selecting samples based on a system of intervals in a numbered population
What is stratified sampling
introduces an extra step before sampling the population: determining groups within our population whose proportions we want our sample to reflect to enhance its representativeness
What is cluster sampling
clusters of individual are identified, and then a subset of cluster is randomly chosen to sample from
What are types of non-probability sampling
convenience sampling
purposive sampling
quota sampling
snowball sampling
What is convenience sampling
a sample is chosen from the people who are available to participate in the research
What is purposive sampling
also known as judgment, selective or subjective sampling. is a sampling techniques in which the researchers rely on their judgment when choosing members of the population to participate in the study
What is quota sampling
similar to stratified sampling but here we use a non-probabilistic sampling technique to determine the sample
What is snowball sampling
this type of sample can be used by researchers looking for a specialised population. Researcher identifies the first participant then asks participant to recommend other potential participant
