S - Data Collection Flashcards
what is simple random sampling and what are its advantages and disadvantages?
a simple random sample of size n is where every sample of size n has an equal chance of being selected
advantages - free of bias, easy and cheap for small samples ad populations, each sampling unit has a known and equal chance of selection
disadvantages - not suitable for large samples and populations, sampling frame needed
what is systematic sampling and what are its advantages and disadvantages?
the required elements are chosen at regular intervals from an ordered list
advantages - simple and quick, suitable for large samples and large populations
disadvantages - a sampling frame is needed, bias introduced if sampling frame is not random
what is stratified sampling and what are its advantages and disadvantages?
the population is divided into mutually exclusive strata and a random sample is taken from each
advantages - sample accurately reflects population structure, proportional representation of group within population
disadvantages - population must be clearly classified into distinct strata, same disadvantages as simple random sampling within each stratum
what is quota sampling and what are its advantages and disadvantages?
an interviewer or researcher selects a sample that reflects the characteristics of the whole population
advantages - allows a small sample to still be representative of the whole population, no sampling frame required, quick easy and inexpensive, easy comparison between different groups within a population
disadvantages - non random sampling can introduce bias, population must be divided into groups which can be costly or inaccurate, increasing scope of study increases number of groups which adds time and expenses, non responses not recorded
what is opportunity sampling and what are its advantages and disadvantages?
sample is taken from people who are available at the time of study and who fit the criteria you are looking for
advantages - easy and inexpensive
disadvantages - unlikely to present representative result, highly dependent on individual researcher
what is cluster sampling and what are its advantages and disadvantages?
starts with sub-groups of the population and items are chosen from one or several of the sub-groups (now called clusters)
advantages - reduces variability, can be taken from multiple areas
disadvantages - bias, requires size equality to be effective
