Probability Distributions > What is the Beta Geometric Distribution? The beta geometric distribution (also called the Type I Geometric) is a type of geometric distribution, where the probability of success parameter, p, has a Beta distribution with shape parameters alpha(α)…

## Area Sampling & Area Frames: Definition, Examples

Sampling > What is Area Sampling? Area sampling involves sampling from a map, an aerial photograph, or a similar area frame. It is often the sampling method of choice when a sampling frame isn’t available. For example, a city map…

## Jackknife Estimator: Simple Definition & Overview

Statistics Definitions > The jackknife (“leave one out”) can be used to reduce bias and estimate standard errors. It is an alternative to the bootstrap method. Comparison to Bootstrap Like the bootstrap, the Jackknife involves resampling. The main differences are:…

## Dagum Distribution: Definition, CDF & PDF

Probability Distributions > The Dagum distribution (also called the Inverse Burr distribution; Dagum called it the generalized logistic-Burr distribution) was proposed by Camilo Dagum in the 1970s to model income and wealth distribution. Dagum developed the models as an alternative…

## M-Estimator: Simple Definition, Usage

Statistics Definitions > The M-estimator is a robust regression method often used as an alternative to the least squares method when data has outliers, extreme observations, or does not follow a normal distribution. While the “M” indicates that M estimation…

## Prediction Error: Definition

Statistics Definitions > Prediction error quantifies one of two things: In regression analysis, it’s a measure of how well the model predicts the response variable. In classification (machine learning), it’s a measure of how well samples are classified to the…

## Operational Statistics: Definition

Statistics Definitions > In general, the term “Operational statistics” refers to a set of statistics that describes operations for a business, organization, or institution. It can also apply to a network, system, or internal operation (for example, a production line).…

## Target Population: Definition, Examples

Statistics Definitions > Target population is an informal term used mostly in epidemiology. It’s general defined to mean a group or set of elements that you want to know more information about. Most of the time, “target population” and “population”…

## Weighting Factor, Statistical Weight: Definition, Uses

Statistics Definitions > Weighting Factor Contents: Weight and the Weighting Factor. Use in Sampling. Use in Nuclear Medicine. Weight Function 1. Weight and the Weighting Factor. A statistical weight is an amount given to increase or decrease the importance of…

## Extra Sums of Squares: Definition

Statistics Definitions > What is Extra Sums of Squares? Extra Sums of Squares (ESS) is the difference in the Error Sums of Squares (SSE) of two models. More specifically, ESS is a measure of the marginal reduction in Error Sums…