Applied Statistics - 1.1 - Populations and Samples Flashcards
What is a population?
The whole set of items that are of interest
Populations can include people, animals, or objects depending on the study.
What is a census?
Observes or measures every member of a population
A census aims to collect complete data for accuracy.
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
Sampling is often used when a census is impractical.
What is an advantage of a census?
- Completely accurate
A census provides a complete picture of the population.
What are the disadvantages of a census?
- Time consuming & expensive
- Cannot be used when the testing process destroys the item
- Hard to process large quantity of data
These factors can limit the feasibility of conducting a census.
What are the advantages of a sample?
- Less time consuming & less expensive than a census
- Fewer people have to respond
- Less data to process than in a census
Sampling is often preferred for preliminary studies or when resources are limited.
What are the disadvantages of a sample?
- Data may not be as accurate
- May not be large enough to reflect about subsets in population
Samples can introduce bias if not properly selected.
What are sampling units?
Individual units of a population
Each sampling unit can be a person, household, or any other distinct entity.
What is a sampling frame?
Sampling units of a population individually named or numbered to form a list
A sampling frame is crucial for ensuring that each unit has a known chance of being selected.
