Chapter 1: Data and Decisions

College level statistics course

Big Data

Big Data

The collection and analysis of data sets so large and complex that traditional methods typically brought to bear on the problem would be overwhelmed

Business analytics

The process of using statistical analysis and modeling to drive business decisions.

Case

A case is an individual about whom or which we have data. Also called a record or row.

Categorical (or qualitative) variable

A variable that names categories (whether with words or numerals)

Context

Ideally tells who was measured, what was measured, how the data were collected, where the data were collected, and when and why the study was performed

Cross-sectional data

Data taken from situations that vary over time but measured at a single time instant are said to be a cross-section of the time series

Data

Recorded values, whether numbers or labels, together with their context

Data mining (or predictive analytics)

The process of using a variety of statistical tools to analyze large databases or data warehouses

Data table

An arrangement of data in which each row represents a case and each column represents a variable

Data warehouse

A large database of information collected by a company or other organization usually to record transactions that the organization makes, but also used for analysis via data mining.

Experimental unit

An individual in a study for which or for whom data values are recorded. Human experimental units usually called subjects or participants.

Identifier variable

A categorical variable that records a unique value for each case, used to name or identify it

Metadata

Auxiliary information about variables in a database, typically including how, when, and where (and possibly why) the data were collected; who each case represents; and the definitions of all the variables

Nominal variable

Can be applied to a variable whose values are used only to name categories

Ordinal variable

Can be applied to a variable whose categorical values possess some kind of order

Participant

A human experimental unit. Also called a subject

Quantitative variable

A variable in which the numbers are values of measured quantities with units

Records

Information about an individual in a database.

Relational database

Stores and retrieves information. Information is kept in data tables that can be “related” to each other.

Respondent

Someone who answers, or responds to, a survey

Spreadsheet

A layout designed for accounting that is often used to store and manage data tables. Excel is a common example.

Subject

A human experimental unit. Also called a participant

Time series

Data measured over time. Usually the time intervals are equally spaced or regularly spaced (e.g., every week, every quarter, or every year).

Units

A quantity or amount adopted as standard of measurement, such as dallars, hours, or grams

Variable

Hold information about the same characteristic for many cases.