Sampling Flashcards
define population
the whole set of items that are of interest
define census
measures every member of the population
advantages + disadvantages of a census
PROS:
- results should be completely accurate
CONS:
- time consuming + expensive
- hard to process large quantity of data
advantages + disadvantages of simple random sampling
PROS:
- free of bias
- easy and cheap for smaller populations
- each sampling unit has an equal and known chance of being selected
CONS:
- sampling frame needed
- not suitable for large samples or populations
how does systematic sampling work
required elements are chosen at regaulr intervals from an ordered list
advantages + disadvantages of systematic sampling
PROS:
- simple + quick to use
- good for larger populations
CONS:
- sampling frame needed
- bias introduced if sampling frame is not random
how to calculate the sample number in stratified sampling
number in stratum/number in population X sample size
advantages + disadvantages of stratified sampling
PROS:
- sample accurately reflects population structure
- proportional representation of group within population
CONS:
- population must be clearly classified into distinct strata
- same disadvantages of simple random sampling within each stratum
define quota sampling
interviewer or researcher selects a sample that reflects the characteristics of the population
advantages + disadvantages of quota sampling
PROS:
- quick, easy + inexpensive
- no sampling frame needed
CONS:
- non-responses are not recorded
- non-random sampling can introduce bias
- population must be divided into groups, which can be costly or inaccurate
what is meant by opportunity/convenience sampling and what are its advantages + disadvantages
sample is taken from people who are available at the time + fits the criteria you are looking for
PROS:
- easy + inexpensive
CONS:
- unlikely to produce an accurate result
- highly dependent on individual researcher
