Regression Analysis > What is the Mahalanobis distance? The Mahalanobis distance (MD) is the distance between two points in multivariate space. In a regular Euclidean space, variables (e.g. x, y, z) are represented by axes drawn at right angles to…

# History Graded Influences: Definition, Examples of Normative

Confounding Variables > What are History Graded Influences? Normative history graded influences are events experienced by a particular culture at a certain period of time. The term normative* here means that the majority of a culture experiences the events —…

# Hamiltonian Cycle: Simple Definition and Example

Graph Theory > A Hamiltonian cycle is a closed loop on a graph where every node (vertex) is visited exactly once. A loop is just an edge that joins a node to itself; so a Hamiltonian cycle is a path…

# Queuing Theory: Simple Definition, Notation and Terminology

Combinatorics > What is Queuing Theory? Queuing theory is the study of queues and the random processes that characterize them. It deals with making mathematical sense of real-life scenarios. For example, a mob of people queuing up at a bank…

# Urn Model: Simple Definition, Examples and Applications

Probability > In statistics, an urn model is an idealized way of modeling real-life problems as if they were problems which involve drawing balls out of an urn, or box. The urn contains balls of two or more colors. Depending…

# Adaptive Sampling: Simple Definition & Examples

Types of Sampling > Adaptive sampling (also called response-adaptive designs) is where you adapt your selection criteria as the experiment progresses, based on preliminary results as they come in. Adaptive sampling is especially important in medical research, where traditional sampling…

# Traveling Salesman Problem and TSP Art

Graph Theory > What is the Traveling Salesman Problem? The Traveling Salesman Problem answers the question “Given a list of cities you want to visit, what’s the shortest possible distance to visit all of them and return to your starting…

# Order Statistics: Simple Definition, Examples

Statistics Definitions > Order Statistics Order Statistics Definition Order statistics are sample values placed in ascending order. The study of order statistics deals with the applications of these ordered values and their functions. Let’s say you had three weights: X1…

# False Discovery Rate: Simple Definition, Adjusting for FDR

Hypothesis Testing > False Discovery Rate Contents: What is the False Discovery Rate? FDR Formula FDR in hypothesis testing FDR in medical testing Adjusting the false discovery rate What is the False Discovery Rate? The false discovery rate (FDR) is…

# Scale Variable: Definition

Types of Variable > What is a Scale Variable? Scale variable doesn’t have an “official” definition; it’s one of those terms that has a slightly different meaning depending on where you’re using it. In a very general sense, the term…