An economic model including the labor resource and the process stage configuration is proposed to design X¯ charts allowing for all the design parameters to be varied in an adaptive way. A random shift size is considered during the economic design selection. The results obtained for a...

This paper presents an economic design of X control charts with variable sample sizes, variable sampling intervals, and variable control limits. The sample size n, the sampling interval h, and the control limit coefficient k vary between minimum and maximum values, tightening or relaxing the...

This paper discusses the mean stationarity of real exchange rates by using new time series methods and new tests. The question whether the real exchange rates have a unit root or are level reverting is set in the general and flexible framework of fractionally integrated processes. The...