## Anscombe residual

Overview page. Subjects: Probability and Statistics.

An alternative to the usual residual (see regression diagnostics) which Anscombe proposed in 1953 for cases where the random errors in a general regression model do not have a normal...

## chi-square distribution

Overview page. Subjects: Mathematics.

In statistics, a probability distribution used to obtain an approximate measure of the discrepancy between sets of observed and expected scores and to perform a chi-square test. If a set of...

## exponential distribution

Overview page. Subjects: Mathematics.

The continuous probability distribution with probability density function *f* given by *f*(*x*)=λ exp(−λ *x*), where λ is a positive parameter, and *x*≥0. It has mean 1/λ and variance 1/λ^{2}. The time...

## leptokurtic

Overview page. Subjects: Biological Sciences — Economics.

Applied to a distribution that is more peaked than a Gaussian distribution (i.e. a few points occur far from the origin, but most are very close to it).

## method of moments

Overview page. Subjects: Probability and Statistics.

An alternative to the method of maximum likelihood as a method of estimating the parameters of a distribution. Each moment of a distribution can be expressed as a function of the parameters...

## nearest-neighbour analysis

Overview page. Subjects: Biological Sciences.

The study of settlements in order to discern any regularity in spacing by comparing the actual pattern of settlement with a theoretical random pattern. For the methodology, see Mak (2003)...

## normal distribution

Overview page. Subjects: Science and Mathematics — Social Sciences.

In statistics, a continuous probability distribution which is asymptotic and symmetrically bell-shaped about the mean. The normal distribution is widely applied in statistics to model...

## Poisson process

Overview page. Subjects: Probability and Statistics.

Description of a situation where events occur randomly in time, or space, in such a way that for each small interval of time, or small region of space, the probability that it contains...

## skewness

Overview page. Subjects: Science and Mathematics — Economics.

An expression of the degree of asymmetry shown on a frequency distribution. A non-skewed distribution is a perfect, normal (Gaussian) distribution. Grain-size distributions are skewed...