Statistics How To

Statistics Definitions > A complete statistic T “… is a complete statistic if the family of probability densities {g(t; θ) is complete” (Voinov & Nikulin, 1996, p. 51). The concept is perhaps best understood in terms of the Lehmann-Scheffé theorem…

Statistics Definitions > Prevalence in statistics Prevalence is the number of disease cases in a population; incidence is number of new cases that develop. Contents: What is Incidence in statistics? What is Prevalence in statistics? 1. Incidence Definition Incidence is…

Probability Distributions > The Kumaraswamy distribution is a two-variable family of distributions that is bounded at one and zero. It is flexible and can be used to model a variety of shapes, and its probability density function and cumulative distribution…

Time Series > The GARCH model, or Generalized Autoregressive Conditionally Heteroscedastic model, was developed by doctoral student Tim Bollerslev in 1986. The goal of GARCH is to provide volatility measures for heteoscedastic time series data, much in the same way…

RCT > Pre-test and post-test probability refers to the probability of having a disease before a diagnostic test is performed (pre-test probability) and after a test is performed (post test probability). How to Determine Pre-Test and Post-Test Probability There are…

Statistics Definitions > Residual Variance (also called unexplained variance or error variance) is the variance of any error (residual). The exact definition depends on what type of analysis you’re performing. For example, in regression analysis, random fluctuations cause variation around…

Probability Distribution: List of Statistical Distributions A severity distribution (or loss severity distribution) is a probability distribution of the amount of losses incurred per operational loss event. As it is a distribution (rather than a single figure or set of…

Statistics Definitions > Fiducial inference (Fisher, 1930) produces a fiducial distribution for parameters without having to specify a prior probability distribution. Savage (1962) aptly described the unusual technique as “…an attempt to make the Bayesian omelette without breaking the Bayesian…

Probability Distribution: List of Statistical Distributions > Copula distributions contain copulas (from the Latin link)—the joint distributions of random variables. They enable us to identify dependencies in multivariate distributions; Any multivariate distribution can be modeled with a separately specified set…

Cointegration > The Engle Granger test is a test for cointegration. It constructs residuals (errors) based on the static regression. The test uses the residuals to see if unit roots are present, using Augmented Dickey-Fuller test or another, similar test.…