Statistics Definitions > > Clustered Standard Errors You may want to read this article first: What is the Standard Error of a Sample? What are Clustered Standard Errors? Clustered Standard Errors(CSEs) happen when some observations in a data set are…
Tikhonov Regularization: Simple Definition
Statistics Definitions > What is Tikhonov Regularization? Tikhonov Regularization (sometimes called Tikhonov-Phillips regularization) is a popular way to deal with linear discrete ill-posed problems. Ill-posed problems violate one of the terms of a well-posed problem. Well posed problems: .Have a…
Inverse Sampling: Simple Definition & Examples
Sampling > What is Inverse Sampling? In inverse sampling (sometimes called standard inverse sampling), you continue to choose items until an event has occurred a specified number of times. It is often used when you don’t know the exact size…
Rao-Blackwell Theorem (Rao-Blackwellization)
Statistics Definitions > You may want to read this article first: What is a Sufficient Statistic? What is the Rao-Blackwell Theorem? The Rao-Blackwell theorem (sometimes called the Rao–Blackwell–Kolmogorov theorem or Rao-Blackwellization) is a way to improve the efficiency of initial…
Stable Distribution: Basic Definition
Probability Distributions > Stable Distribution What is the Stable Distribution? Stable distributions are a general family of probabilities distributions that share certain properties. They were first described by Paul Lévy (1925) and so are also sometimes informally called Lévy distributions.…
Sheppard’s Correction: Definition
Moments > Sheppard’s Correction for Grouping Errors are adjustments to calculated sample moments for grouped data (i.e. data that has been binned). The correction is named after W.F. Shepard, who noted than when moments are calculated for continuous frequency distributions,…
Shifting Data
Statistics Definitions > Shifting data is adding a constant k to each member of a data set, where k is a real number. In visual terms, it is lifting the entire distribution of data points and shifting en masse a…
What is Rescaling Data?
Statistics Definitions > Rescaling data is multiplying each member of a data set by a constant k; that is to say, transforming each number x to f(X), where f(x) = kx, and k and x are both real numbers. Rescaling…
Variance Sum Law
Statistics Definitions > What is the Variance Sum Law? The Variance Sum Law determines the variance of a sum (or difference) when you know the variance of the component parts. For example, suppose you ran a research project which involved…
Turning Point Test: Simple Definition
Statistics Definitions > What is the Turning Point Test? The turning point test is a test which lets us check whether a set of random variables are independent and identically distributed. Proposed by Irénée-Jules Bienaymé in 1874, this test is…