## Aalen model

Overview page. Subjects: Probability and Statistics.

A linear regression model describing the manner in which the expected value of a response variable, *Z*(*t*), depends on explanatory variables *X*
_{1}(*t*),…, *X*
*null...*

## Abraham de Moivre

Overview page. Subjects: Probability and Statistics.

(1667–1754; b. Vitry, France; d. London, England)

French mathematical prodigy. De Moivre studied at U Sedan when aged eleven, and later at U Saumur and the Sorbonne. In 1688 he...

## Abraham Wald

Overview page. Subjects: Probability and Statistics — Economics.

(1902–50; b. Cluj, Romania; d. Travancore, India)

Hungarian geometer and statistician. Wald gained his PhD in geometry in 1931 from U Vienna. In 1938, on the Nazi seizure of...

## absolute difference

Overview page. Subjects: Probability and Statistics.

The absolute value of the difference between two numbers. See also mean deviation.

## acceptance region

Overview page. Subjects: Probability and Statistics.

The set of values of the statistic, in a hypothesis test, which lead to acceptance of the null hypothesis.

## acceptance sampling

Overview page. Subjects: Probability and Statistics.

A method of quality control. A random sample is taken from a batch of output and the decision to accept or reject the batch is based on either the number of defectives in the sample...

## acceptance–rejection algorithm

Overview page. Subjects: Probability and Statistics.

A method for generating values of a continuous random variable for use in a simulation. Suppose that the random variable *X*, which takes values in the interval (*a*, *b*), has probability...

## acquiescence bias

Overview page. Subjects: Probability and Statistics.

The tendency of an interviewee to agree with the questioner. For example, if the question is ‘Did you vote in the last election?’ then the number replying ‘Yes’ is likely to provide an...

## adaptive sampling

Overview page. Subjects: Probability and Statistics.

A method of sequential sampling in which the later sampling procedure is affected by the earlier results. Examples include the comparison of rival treatments in clinical trials and the use...

## addition law

Overview page. Subjects: Probability and Statistics.

If *A* and *B* are two events then the addition law states that the Pr(*A* or *B*)=Pr(*A*)+Pr(*B*)−Pr(*A* and *B*), or using set notation *P*(*A*∪*B*)=*P*(*A*)+*P*(*B*)−*P*(*A*∩*B*). In the special case where A and B are...