Testing randomness against ordered alternatives in a multinomial experiment with grouped frequencies

A test is derived for homogeneity of probabilities of a multi nomial trial against ordered alternatives, applicable to cases in which only the frequencies of grouped categories are known. Its asymptotic null distribution is obtained.     

Modified Tukey's Control Chart

Phase I of control analysis requires large amount of data to fit a distribution and estimate the corresponding parameters of the process under study. However, when only individual observations are available, and no a priori knowledge exists, the presence of outliers can bias the analysis. A relatively recent and successful approach to address this situation is Tukey's Control Chart (TCC), a charting method that applies the Box Plot technique to estimate the control limits. This procedure has proven to be effective for symmetric distributions. However, when skewness is present the average run length performance diminishes significantly. This article proposes a modified version of TCC to consider skewness with minimum assumptions on the underlying distribution of observations. Using theoretical results and Monte Carlo simulation, the modified TCC is tested over several distributions proving a better representation of skewed populations, even in cases when only a limited number of observations are available.     

Is Arbitration Habit Forming? The Narcotic Effect of Arbitration Use

This paper explores the existence of structural state dependence in arbitration use where it is legally mandated to resolve labor–management bargaining disputes. Previous studies have found both positive state dependence (the narcotic effect) and negative state dependence. This paper reports a negative state dependence for the Minnesota public sector during the period 1973 to 1980. A weak positive trend in arbitration probabilities and a positive relationship between current arbitration probabilities and the proportion of bargainers engaging in arbitration during the same calendar year are also found. An analysis of the dynamic implications of these findings does not support fears that compulsory arbitration schemes are unstable or lead to arbitration as the dominant settlement mode.