4 papers · 1 filter
On the conditional distribution of the mean of the two closest among a set of three observations
I. J. H. Visagie, F. Lombard
Chemical analyses of raw materials are often repeated in duplicate or triplicate. The assay values obtained are then combined using a predetermined formula to obtain an estimate of…
CUSUM ARL - Conditional or Unconditional?
F. Lombard, D. M. Hawkins
The behavior of CUSUM charts depends strongly on how they are initialized. Recent work has suggested that self-starting CUSUM methods retain some dependence on their very first rea…
Signed Sequential Rank CUSUMs
F. Lombard, C. Van Zyl
CUSUMs based on the signed sequential ranks of observations are developed for detecting location and scale changes in symmetric distributions. The CUSUMs are distribution free and…
Nonparametric Cusum Charts for Angular Data with Applications in Health Science and Astrophysics
F. Lombard, Douglas M. Hawkins, Cornelis Potgieter
This paper develops non-parametric rotation invariant CUSUMs suited to the detection of changes in the mean direction as well as changes in the concentration parameter of angular d…