Population and samples

What is a population

• Whole set of items that are of interest

What is a census

• Observes or measures every member of a population

What is a sample

• A subset of the population intended to represent the population

What is a sampling unit

• Individual unit of a population

What is a sampling frame

• Sampling units that is individually named or numbered to form a list called a sampling frame

Advantage of a census

• Should give completely accurate results

Disadvantage of a census

• Time consuming and expensive

• Cannot be used when testing process destroys the item

• Hard to process large quantity of data

Advantage of a sample

• Less time consuming than census

• Fewer people have to respond (quick)

• Less data to process

Disadvantage of a sample

• Data may not be as accurate

• May not be large enough to represent small subgroups of population