Flashcards in stats Deck (20):
set of data values for a random variable
a group that you want to sample information about.
a collection of the items available to be sampled
when information is collected from a small representation of the population
the person/object to be sampled
the proportion of available sampling units that are actually sampled
when all the population has information collected about them
simple random sampling
every item in a population has an equal chance of being chosen. each item is assigned an ID and a random number table/generator is used to chose a random sample of numbers. suited to a small population.
sampling due an easy opportunity. leads to bias and an unrepresentative sample however useful for initial studies
the population is divided into categories then a random sample is chosen from each category.
each categories size is proportional with the population.
the population is divided into strata representative of the population. a random sample of clusters is chosen and every item in the chosen clusters is sampled.
a large number of small clusters is most accurate.
a simple rule/pattern is used to chose the sample. Every item in the sampling frame is listed and every nth term is selected.
simple and quick but may be unrepresentative if a pattern exists in the list
the population is divided into groups and a given number from each group is sampled.
cheap and quick
where people volunteer to taake part or are given a choice to participate.
may be bias as people may chose to express their opinions of certain matters.
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