Statistics Definitions > A sample statistic is a piece of statistical information you get from a handful of items. A sample is just a part of a population. For example, let’s say your population was every American, and you wanted…

## Bates Distribution: Definition

Probability Distributions > What is the Bates Distribution? The Bates Distribution (also called the rectangular mean distribution) is the distribution of the mean of n independent standard uniform variates (from 0 to 1). The distribution was derived by Grace Bates…

## Huynh-Feldt Correction: Definition, Formula

ANOVA > Huynh-Feldt Correction The Huynh-Feldt correction is a correction for violations of sphericity. If Mauchly’s Sphericity Test test returns a small p-value, you should apply a correction to the index of non sphericity (called the Box index, ε): When…

## Spectrum Bias: Simple Definition, Causes

Types of Bias > Spectrum Bias What is Spectrum Bias? Spectrum bias (or case-mix bias) is the variability of medical test performance that happens when tests are given to different mixes of patients at different locations. Test performance may differ…

## Replication and Replicability: Simple Definition, Examples

Experimental Design > Replication and Replicability Contents: Replication Replicability What is Replication? In experimental design, replication is where each treatment is assigned to many participants. Or, the entire experiment is repeated on a large group of subjects. The process: Improves…

## One to One: Definition

Statistics Definitions > A one to one function is a relation that preserves “distinctness”; Every unique member of the function’s domain is mapped to a unique member of its range. Sometimes this type of mapping is called injective. Both images…

## Antecedent Variable: Definition & Examples

Types of variables > An antecedent variable (or antecedent confounding variable) happens before the independent variable and dependent variable. It may affect the relationship between the two variables, or it might just affect the two variables separately, without their being…

## Ipsative: Simple Definition, Examples

Statistics Definitions > In psychology, ipsative measurement refers to a particular type of survey or assessment in which a respondent is forced to choose among several generally desirable options. Unlike normative tests, where a respondent answers questions with scaled responses,…

## Cross Validation (Statistics)

Statistics Definitions > What is Cross Validation? Cross validation (also called rotation estimation, or out-of-sample testing) is one way to ensure your model is robust. A portion of your data (called a holdout sample) is held back; The bulk of…

## Objective Probability (Frequency)

Probability > Objective Probability What is Objective Probability? Objective probability (also called frequency probability) is associated with random events like dice rolls, choosing bingo balls, or your numbers coming up in the lottery. The term is mostly used in philosophy…