Glossary
Observations
In research, observations—also called, cases, objects, or research units—are the entities that a study focuses on. They are the “things” about which data are collected and analyzed. Depending on the discipline and research question, observations may ...
Variables
A variable is a measurable characteristic or attribute that can take on different values across cases (i.e., observational units such as people, companies, or time points). Types of Variables Variables can be classified by the type of values they ...
Research Units
In research, research units—also called objects or cases—are the entities that a study focuses on. They are the “things” about which data are collected and analyzed. Depending on the discipline and research question, research units may be ...
Cases
In research, cases—also called objects or research units—are the entities that a study focuses on. They are the “things” about which data are collected and analyzed. Depending on the discipline and research question, cases may be individuals, groups, ...
Objects (in Research)
Objects (in Research) In research, objects—also called cases or research units—are the entities that a study focuses on. They are the “things” about which data are collected and analyzed. Depending on the discipline and research question, objects may ...
Empty Model
Empty Model (Null Model) An empty model is a statistical model that describes a quantitative outcome variable using only a single overall value, typically the mean of the response. It is called empty because it contains no explanatory (predictor) ...
Data
Data Data are recorded observations, measurements, or information collected to answer questions, test hypotheses, or make decisions. In statistics and data science, data are the raw material we analyze to discover patterns, relationships, and ...
Vectors
Vectors Vectors are one of the most basic and important data structures in R. A vector is an ordered collection of values of the same data type, such as numbers, characters, or logical (TRUE/FALSE) values. In statistics and data science, vectors are ...
R Objects
R Objects Overview In R, everything is an object. Data, functions, models, and even results of calculations are all stored as objects. Understanding R objects is fundamental to working with data, writing reproducible code, and performing statistical ...
Arguments (in R Functions)
Arguments (in R Functions) R function arguments are the inputs provided to a function that determine how it runs and what results it produces. Arguments are placed inside the parentheses of a function call and may represent data, options, or control ...
R Function
An R function is a reusable block of code in the R programming language that performs a specific task. Functions accept inputs (called arguments), execute a set of instructions, and return an output. They are fundamental to writing efficient, ...
Statistical Model
A statistical model is a simplified way of describing how data are generated. It helps us separate what we can explain using known information from what we cannot explain perfectly. We use statistical models for three main purposes: (1) to understand ...
Data Generating Process (DGP)
Data Generating Process (DGP) The Data Generating Process (DGP) refers to the underlying mechanism—real or hypothetical—that produces the data we observe. A DGP specifies how variables are related, how randomness enters the system, and how observed ...
Popular Articles
tally()
The tally() function will count, or tally, the number of cases that are observed in each category of a variable. Example 1: Use tally() to count the number of observations in each category of a categorical variable. # Use tally() to count the number ...
desc()
The desc() function can be used with the arrange() function to arrange a variable in a data frame in descending order. Example 1: For instance, when we use the arrange() function to sort the Fingers data frame by Thumb, it will sort the values for ...
favstats()
The favstats() function will compute a set of common summary statistics ("favorite stats") for a given variable, including the five-number summary (minimum, Q1, median/Q2, Q3, maximum), the mean, the standard deviation, the sample size (n), and the ...
arrange()
The arrange() function will arrange a data frame by a specific variable, in ascending order. You can use the desc() argument with the arrange() function to arrange the data frame in descending order. NOTE: The arrange() function is similar to the ...
Statement on Sex and Gender
Many people use sex and gender interchangeably, but in truth, they’re distinct concepts. Sex is a classification based on biological characteristics, including DNA and anatomy. Gender refers to the socially constructed roles, behaviors, ...