S: Collecting and Interpreting Data Flashcards
What is meant by the target population?
all the members of the population you would ideally like to get the information from
What is a census?
a survey that gives a picture of society
What is a sampling frame?
a list of the target population
What is a simple random sample?
every possible sample of given size is equally likely to be selected
What is cluster sampling?
the target population is divided into naturally occurring subgroups, then a sample is taken from the clusters
What is systematic sampling
A starting point is chosen then items are systematically chosen a certain number apart
What is stratified sampling?
The target population is divided into groups based on some characteristic, called strata. Within each stratum, a probability is selected
What is proportional stratified sampling?
the frequencies for each group in the sample are proportional to the frequencies for each group in the target population
What is opportunity sampling?
using people from the target population available at the time and willing to take part
What is self-selected sampling?
when the individuals in the sample have chosen to be in sample
What are the advantages of stratified sampling?
- Representative if the sampling frame is available
- the frequencies for each group in the sample can be proportional to the frequencies for each group in the population
What are the disadvantages of stratified sampling?
- not possible without a sampling frame
- strata must be carefully defined
- sometimes difficult to split the population into naturally occurring groups
- there may be missing values in the sample
What are the advantages of quota sampling?
does not need a sampling frame
What are the disadvantages of quota sampling?
- non-random
- may not be representative of the target population and could be biased
What are the advantages of opportunity sampling?
- quick and easy
- convenient
