This article presents an educational exercise in which statistical process control charts are constructed and used to identify the Steroids Era in American professional baseball. During this period (roughly 1993 until the present), numerous baseball players were alleged or proven to have used banned, performance-enhancing drugs. Also observed during this period was an increase in offensive perf...

When an assignable cause(s) manifests itself to a multivariate process and the process shifts to an out-of-control condition, a root-cause analysis should be initiated by quality engineers to identify and eliminate the assignable cause(s) affected the process. A root-cause analysis in a multivariate process is more complex compared to a univariate process. In the case of a process involved seve...

class AbstractList { //@ model public int size; //@ in isEmpty; //@ model public boolean isEmpty; //@ public represents isEmpty <(size == 0); //@ public invariant size >= 0; //@ assignable isEmpty; //@ ensures isEmpty; abstract public void clear(); //@ assignable size; // but isEmpty is not assignable //@ ensures size <= \old(size); //@ ensures \old(size) > 0 ==> size > 0; abstract public void ...

Duncan first proposed the economic design of x control charts in 1956 to control normal process means and ensure that an economic design control chart actually lowers the cost, compared with a Shewhart control chart. Many authors have studied the control charts from economic viewpoint from then on. An economic design does not consider the statistical properties, such as type I or type II error ...

When a change occurs in a process, one expects to receive a signal from a control chart as quickly as possible. Upon the receipt of signal from the control chart a search for identifying the source of disturbance begins. However, searching for assignable cause around the signal time, due to the fact that the disturbance may have manifested itself into the rocess sometimes back, may not always l...

Control Chart Patterns (CCPs) recognition is one the most important concepts in control chart application. Relating the patterns exhibited on the control chart to assignable causes is an ambiguous and vague task especially when multiple patterns co-exist. In this study, a fuzzy rule-based system is developed for X ̅ control charts to prioritize the control chart causes based on the accumulated e...

This paper presents a syntactic method to check so-called assignable clauses of annotated Java programs. Assignable clauses describe which variables may be assigned by a method. Their correctness is crucial for reasoning about class specifications. The method that we propose is incomplete, as it only makes a syntactic check and it does not take aliasing or expression evaluation into account, bu...

Despite their fame and capability in detecting out-of-control conditions, control charts are not effective tools for fault diagnosis. There are other techniques in the literature mainly based on process information and control charts patterns to help control charts for root cause analysis. However these methods are limited in practice due to their dependency on the expertise of practitioners. I...

A proper monitoring of stochastic systems is the control charts statistical process and drift in characteristics output may be due to one or several assignable causes. Although many research works have been done on economic design with single cause, T^2 chart under Weibull shock model multiple causes considering multivariate Taguchi loss function has not presented yet. Using concept quality lea...

The Capability Maturity Model for Software is a model for building organizational capability that has been widely adopted in the software community and beyond. The Software CMM is a five-level model that prescribes process improvement priorities for software organizations. Level 4 in the CMM focuses on using quantitative techniques, particularly statistical techniques, for controlling the soft...