WORKSHEET #1 STA 291 (022-024) Fall 2009 Terminology Population – Total set of all subjects of interest Elementary Unit – Any individual member of the population Sample – Subset of the population from which the study actually collects information Variable – A characteristic of a unit that can vary among subjects in the population/sample Parameter – Numerical characteristic of the population Statistic – Numerical characteristic of the sample Descriptive Statistics – Summarizing the information in a collection of data Inferential Statistics – Using information from a sample to make conclusions/predictions about the population Qualitative Variable – Variable without numerical values associated with them Nominal – scale of unordered categories Ordinal – scale of ordered categories Quantitative Variable – Variable with numerical values associated with them Scale of measurement is Ordinal Discrete Variable – takes on a finite number of values Continuous Variable – takes on an infinite continuum of possible real number values Ask yourself, can you be more specific? Can you find a value in between? Example Suppose a UK student, we’ll call him George, wants to conduct a survey about Kentucky High School students and hands out his survey to high school students at Lexington Catholic, Henry Clay, and Paul Laurence Dunbar. From a study in 2005, it was already known that 82% of high school students in Kentucky said they were going to apply to go to college. George’s survey revealed that 64% of the students were going to apply to go to college. George used the information from his survey to determine that at least 60% of high school students in Kentucky were going to apply to go to college. Identify the following… Population Elementary Unit Sample Parameter Statistic An example of Descriptive Statistics An example of Inferential Statistics Is the variable qualitative or quantitative? Is the variable Discrete or Continuous?