Stats 1 Flashcards
What is a population?
The whole set of items that are of interest
What does a census do?
Observes or measures every member of a population
What is a sample?
A selection of observations taken from a subset of the population which is used to find out information about the population as a whole
What is systematic sampling?
The required elements are chosen at regular intervals from an ordered list l
What is stratified sampling?
The population is divided into mutually exclusive strata and a random sample is taken from each
What is quota sampling?
An interviewer or researcher selects a sample that reflects the characteristics of the whole population
What is opportunity sampling?
Consists of taking the sample from people who are available at the time the study is carried out and who fit the criteria you are looking for
What are the advantages of simple random sampling?
-No bias
-Easy and Cheap
What are the disadvantages of simple random sampling?
-Not suitable for large populations sizes, as its time-consuming and possibly expensive
-Sampling frame is needed
What are the advantages of systematic sampling?
-Simple and quick to use
-Suitablee for large samples and populations
What are the disadvantages of systematic sampling?
-Sampling frame needed
-Can introduce bias if sampling frame is not random
What are the advantages of stratified sampling?
-Sample accurately reflects the population
What are the disadvantages of stratified sampling?
-Population must be clearly classified into distinct strata
-Each strata suffers from same disadvantages as random sampling
What are the advantages of quota sampling?
-Allows small sample to be representative of population
-No sampling frame needed
-Quick, easy and inexpensive
-Allows for easy comparison
What are the disadvantages of quota sampling?
-Non-random sampling can introduce bias
-Non-responses are not recorded as such
