Stats - introduction Flashcards
Define Population
the whole set of items that are of interest.
Define Sample
some subset of the population intended to represent the population
Define Sampling unit
Each individual thing in the population that can be sampled is known as a sampling unit
Define Sampling frame
Often sampling units of a population are individually named or numbered to form a list called the sampling frame
Define Census
Data collected from the entire population is known as a census
State the advantages of a census
Should give completely accurate result.
State the disadvantages of a census
Time consuming and expensive.
Can not be used when testing involves destruction.
Large volume of data to process.
State the advantages of a sample
Cheaper.
Quicker.
Less data to process
State the disadvantages of a sample
Data may not be accurate.
Data may not be large enough to represent small sub-groups.
What is a parameter
A calculation of a sample or population, usually mean, 𝜇
What is the goal when collecting data
When collecting data, the goal is for the parameters
derived in the sample to be as close to the population as possible
When structuring samples, what undesirable thing may occur
can introduce sampling error and bias
Define bias and sampling error
sampeling error: The difference between the actual value of a parameter and the value derived from a sample
bias : A systematic error in the collection of the sample
How might sampling error/bias occur
Sample is not representative of the population
Leading questions
The wrong person asking questions
Small sample size
- Larger samples are more accurate
