periodicity
is the problem to watch out for when using systemic sampling - happens whenn the list is ordered in systemic order
List three sources of bias related to sampling.
- non response
- the sampling frame
- not using a random method to sample
what are the four types of probability sampling
- Simple random sample
- Systematic sample
- Stratified random sampling
- Multi-stage cluster sampling
what is the non-probabilty sampling?
Does not use random selection methods, associated
with qualitative research
what is probably sampling?
Uses random selection methods, associated with
quantitative methods
what does sampling error mean?
error between the sample and the reality you based the sample from
what is simple sampling?
each person has the same probability of being selected
how is a simple random sample ratio made?
the sample size/population ratio
what is systemic random sample?
you start at a certain place, then you sample every “certain number” in that list
what is the disadvantage of using a systemic sample
eventually you will hit a group where they are all the same
what is stratified random sampling?
makes sure each population is is proportionally represented
what is multi-stage cluster sampling?
used for large populations where they are divided into groups than randomly selected forms those groups
what is standard error?
that 95% of the samples means lie 1.96 from the standard errors
what decreases standard error?
increases sample size
what are the types of non probability sampling?
- Convenience sampling
- Snowball sampling
- Quota sampling
what is convenience sampling and what is the problem with it?
using cases that are readily available to include, the problem is you can’t generalize the results
what is snowball sampling and what is the problem with it?
a type of conveinence sampling
the participants are asked to provide contacts for more participants
what is quota sampling and what is the problem with it?
selecting a specific number of cases, and specific proportions
its most likely not representative
describe how to assess sampling quality
- look at the sampling frame
- is there enough coverage of the populations
- is there information about non responders
- is the response rate high enough to have confidence about the representativeness of the above
