STA 309 Lecture 2: Lecture 2 Notes- Data and Categorical Variables
Document Summary
The rows of a data table correspond to individual cases about whom we record some characteristics. These (cid:272)ha(cid:396)a(cid:272)te(cid:396)isti(cid:272)s (cid:373)ay (cid:271)e (cid:272)olle(cid:272)ted o(cid:374) o(cid:396) a(cid:271)out : respondents: individuals who answer a survey, experimental units: animals, plants, websites, or other inanimate objects (each. Subjects or participants: people in an experiment case is about one individual) The characteristics recorded about each individual or case are called variables: these are usually in columns. Metadata: typically contains information about how, when, and where (possibly why) the data was collected; who each case represents; and definition of variable. Data tables are cumbersome for complex data sets so often 2 or more separate data tables are linked together in a relational database so that information can be merges across them. Each data table in the db is a relation because it is about a specific set of cases with information about each of these cases for all the variables.
