Data Collection Flashcards
What does a census do
A census observed 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 information about the population as a whole
Advantage of a census?
Should give a completely accurate result
Disadvantage of a census?
Time consuming and expensive
Advantage of a sample?
Less time consuming and expensive than a census
Less data to process
Disadvantage of a sample
May not be as accurate
Introduces bias
Define population
The whole set of items that are of interest
What is systematic sampling?
The required elements are chosen at regular intervals from ordered list
What is a simple random sample?
A simple random sample of size n is one where every sample of size n has an equal chance of being selected
What is stratified sampling
The population being divided into mutually exclusive strata (e.g: makes and females) and a random sample is taken from each
Advantage of simple random sampling?
Free of bias
Each sampling unit has an equal chance of being selected
Disadvantage of using simple random sampling
Not applicable to large sample/population sizes
Sample frame required
Advantage of systematic sampling
Simple and quick to use
Suitable for large populations and samples
Disadvantage of systematic sampling
Sampling frame require
Introduces bias if not random
Advantage of stratified sampling
Accurately reflects the population structure
