- Identify the subject, case, and observational unit of a statistical study
- Name and classify variables by type
Population, Sample, Parameters, and Statistics
Samples are subgroups of individuals collected from a population of individuals.
A parameter is a numerical summary of a characteristic (variable of interest) of a population.
Ex. 40% of all Americans aged 18 – 24 are enrolled in college[1]. The population parameter is 40%.
A statistic is a numerical summary of a sample.
Ex. Suppose a random sample of 100 Americans aged 18 – 24 is taken; 35 of them are enrolled in college. The statistic is [latex]\dfrac{35}{100}=35\%[/latex].
Just remember…
Parameters are associated with Populations.
Statistics are associated with Samples.