Abscissa See Cartesian coordinates.
Absolute difference The absolute value of the difference between two
numbers. See also mean deviation.
Absolute value (modulus) The value of a number disregarding its sign.
Denoted by a pair of ‘!’ signs: thus the modulus of -2.5 is !-2.5! = 2.5.
Absorbing barrier (absorbing state) See Markov process.
Acceptable quality level See acceptance sampling.
Acceptance region The set of values of the statistic, in a hypothesis
test, which lead to acceptance of the null hypothesis.
Acceptance-rejection algorithm 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 density function f. Denote the maximum value of f(x) by M. Let u and
v be two random numbers uniformly distributed in the interval (o,1). Writer r=a+(b-a)u
and s= Mv, so that r and s are uniformly distributed on (a,b) and (0,M),
respectively. Calculate f® if f(r) > s then r is accepted as a value of X.
Otherwise, it is rejected and a new pair of values is taken for u and v. See