A systematic theory of optimal stopping emerged with the work by Wald on the optimality of the sequential

probability ratio test (SPRT) [12].

Wald [11] introduced a sequential

probability ratio test (SPRT) which requires substantially fewer observations than a fixed sample size test.

standard as a

probability ratio test that avoids the Conjunction

I use the Wald's Sequential

Probability Ratio Test (SPRT) to help determine the number of periods needed and the costs involved.

he applied the result of Wald and Wolfowitz (1948) to conclude that there is a unique class of optimally efficient uniformats, given by the Sequential Probability Ratio Test, and that it is {[W.sub.n]} (n = 1,2,3, ...) where [W.sub.n] is the uniformat in which the winner is the first player to achieve a lead of n points over his opponent.

(1948) Optimum character of the sequential probability ratio test. Annals of Mathematical Statistics 19 326-339.

(1990) A method for determining the asymptotic efficiency of some sequential probability ratio tests. Australian Journal of Statistics 32(1) 191-204.

(roughly) equivalent to the application of the sequential probability ratio test in reverse" (Johnson, 1961).

Foundational to these sampling plans and control charts is the sequential probability ratio test which makes possible such evaluations after each observation.

The calibrator provides precision measurement and simulation of sequential

probability ratio tests, portable remote terminals, and a range of industrial resistance-temperature detectors, along with ANSI and international thermocouple types.