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…

## Statistical Stability: Definition, Examples

Statistics Definitions > Statistical stability is how well the results of your study or experiment hold up. More specifically, it’s a measure of how well you control for random errors in your study. Statistical stability can be defined more precisely…

## Cross Correlation

Correlation > Cross Correlation in Statistics In statistics, a cross-correlation function is a measure of association. For example, the most common correlation coefficient, the Pearson product-moment correlation coefficient (PPMC), is a normalized version of a cross-correlation. The PPMC gives a…

## Measures of Position

Descriptive Statistics > Measures of position give us a way to see where a certain data point or value falls in a sample or distribution. A measure can tell us whether a value is about the average, or whether it’s…

## Identification Key: Definition & Examples

Statistics Definitions > An identification key is an identification tool primarily used to find taxonomic levels (e.g. species or genus) in the biological sciences. The keys have a wide variety of applications, including identification of plants, nuts, and amphibians as…

## Exponential Power Distribution: Definition, PDF

Probability Distributions > The exponential power distribution is a generalization of the normal distribution. Therefore, it’s also known as the generalized normal distribution. Other names include the General Error Distribution and the Generalized Power Distribution. PDF of the Exponential Power…

## Mean Absolute Scaled Error: Definition, Example

Statistics Definitions > What is Mean Absolute Scaled Error? Mean Absolute Scaled Error (MASE) is a scale-free error metric that gives each error as a ratio compared to a baseline’s average error. The advantages of MASE include that it never…

## Risk Function: Definition

Statistics Definitions > What is a Risk Function? The risk function is the expected value of a loss function. In other words, it’s the expected value of a loss. Most losses are not random; They are usually a result of…