title: Further aspects of a Markovian sampling policy for water quality monitoring.
abstract: In this paper, a Markov process is developed as a mathematical model to study the general problem of quality control monitoring. This approach was previously used by Arnold (1970) in development of sampling plans to study the water quality monitoring of streams. Arnold considered the expected sample size required for various sampling plans. Thre present authors have extended Arnold's work and derived equations for the variance of the sample size. In addition, approximation schemes are developed that could greatly enhance the implementation of this sampling procedure. Techniques are presented showing that an accurate approximation to the expected sample size can be obtained simply by the use of a hand calculator and equations developed within the paper. Moreover, accurate approximations for the variances of sample size can easily be obtained.
mesh_terms: D011786:Quality Control; D013223:Statistics as Topic; D014881:Water Supply / Q000592:standards*