Survey designs Flashcards
Definition of Sampling frame.
Sampling frame is a list of people in the population.
Definition of sample.
Sample is a smaller group of people from the population.
Definition of element.
element is a unit of data e.g. one person.
Definition of population.
Population is every person in a group that the researcher is interested in.
Definition of Snowball sampling
is a type of non-probability sampling that involves existing participants recruiting other participants.
Definition of Census
Census is the whole population of interest.
Why do we do sample instead of census?
We use a sample instead of a census in a study because a census would be very time consuming and expensive.
What are the two types of sampling?
The two types of sampling are probability sampling and non-probability sampling. Probability sampling is when everyone in a population has an equal chance of being in the sample. Non-probability sampling is when everyone in a population does not have an equal chance of being in the sample.
Definition of Probability sampling
Probability sampling is when everyone in a population has an equal chance of being in the sample.
Definition of Non-probability sampling
Non-probability sampling is when everyone in a population does not have a equal chance of being in a sample.
Definition of Accidental (opportunity) sampling
Accidental sampling = is a type of non-probability sampling. Accidental sampling is choosing people who are easy to reach to be in the sample.
Definition of Purposive sampling
Purposive sampling = is a type of non-probability sampling. Purposive sampling is using your own judgement to decide who should be in the sample.
Definition of Quota sampling
Quota sampling = is a type of non-probability sampling. Quota sampling involves choosing people who represent the population.
Definition of simple random sampling
Simple random sampling is a type of probability sampling it involves randomly choosing people by giving people unique numbers and numbers are chosen from a hat randomly.
Definition of 2-stage random sampling
2-stage random sampling is a type of probability sampling. it is when a population is divided into groups and people are chosen from each group.
Definition of Stratified sampling
Stratified sampling is a type of probability sampling. Stratified sampling is when a population is divided into groups called strata. Each strata (group) has similar characteristics.
Definition of Multi-stage Stratification.
Multi-stage stratification is a type of probability sampling. Multi-stage stratification is when a large population is divided into stages.
Definition of cluster sampling.
Cluster sampling is a type of probability sampling. Cluster sampling is when a population is divided into pre-exisiting clusters.
Definition of systematic sampling.
Systematic sampling is a type of probability sampling. Systematic sampling is when people are chosen at a regular interval e.g. every 10th person.
What is the difference between probability sampling and non-probability sampling?
Probability sampling is when everyone in a population has an equal chance of being chosen. Non-probability sampling is when everyone in a population does not have a equal chance of being chosen.
Definition of stratification
Stratification means dividing people into groups.
Why is bias bad?
Bad makes the sample unrepresentative of the population.
Definition of cross sectional study.
Cross sectional study analyses data at one single point in time.
Definition of longitudinal study.
Longitudinal study analyses data over an extended period of time.
Definition of Prevalence rate
Prevalence rate is the amount of people who have a condition at one point in time.
Definition of Period prevalence rate
Period prevalence rate is the amount of people who have a condition during a specific period of time.
Definition of Incidence rate.
Incidence rate is the amount of people who have developed a condition during a period of time. so it is the number of new cases during a period time.
what is a good standard error?
Two standard errors above or below the mean gives a 95% confidence interval?
successive cross sectional
successive cross sectional is looking at 2 or more groups of people of different ages and comparing them over an extended periof of time.
advantages and disadvantages of cross sectional
cross sectional study is less expensive and less time-consuming but cross sectional study is bad because there is a possible of confounding variables.
advantages and disadvantages of longitudinal
Longitudinal study gives a better idea of cause and effect relationship but it is time consuming and expensive.
