MATH 2311Chapter 6

Sampling:Terms:Population – each element (or person) from the set of observations that can be madeSample – a subset of the populationCensus – systematically getting information about an entire populationSampling – studying a part (a sample) in order to gain information about an entire groupSampling Frame – the list of individuals from which a sample is actually selected

Types of Sampling –Voluntary Response sample – people who choose themselves by responding to a general appeal (over represents people with strong opinions)A simple random sample (SRS) consists of individuals from the population chosen in such a way that every set of individuals has an equal chance to be the sample actually selected.A probability sample gives each member of the population a known chance to be selected.A stratified sample divides the population into groups of similar individuals, called strata, and chooses a SRS in each stratum and combines these to form the full sample.In multistage sample design samples are taken from various subsets of the population until a manageable number of samples to interview are arrived upon.Convenience sampling is a non-probability type of sample where the sample is chose based on their convenient accessibility and proximity.

Random Digits•A table of random digits is a long string of the digits 0 – 9 where each entry in the table is equally likely to be any of the 10 digits and the entries are independent of each other.