Rebates, inventories, and intertemporal price discrimination

We demonstrate that universally redeemed rebates can increase manufacturer profits by reducing the incentives of downstream retailers to hoard inventories when optimal wholesale prices vary predictably over time. By bypassing retailers and making direct contracts with buyers, the manufacturer can increase the variations in effective prices paid by consumers without concomitantly creating larger incentives for retailers to hold inventories. During profitable, high-demand periods, manufacturer revenues are ordinarily constrained by'competition'from retailer inventories, thus limiting profits. However, by selectively offering rebates to consumers while maintaining high wholesale prices, low-demand periods can be accommodated without inducing retailer hoarding.     

The Emerging Problems of Alcohol and Substance Abuse in Late Life

Treatment of substance abuse among older adults will become increasingly important as the number of aged Americans increases. The abuse of psychoactive substances is a major contributor to excess morbidity, mortality, and homelessness among persons of all ages and socioeconomic strata regardless of race or ethnicity. Alcohol and tobacco accountfor the majority of substance abuse-related death and disability in the United States; the former through cerebrovascular and hepatic disease, accidents and violence, the latter through chronic pulmonary disease and malignancy. Patterns of substance abuse in late life are substantially different from those observed among younger adults. However, treatment may be less challenging. Effective diagnosis and treatment requires a nonpunitive, supportive, but persistent approach. This means the capacity to collect a substance intake history and the ability to formulate a treatment plan or referral strategy to an addiction specialist or residential treatment setting. It is also important for the practitioner to manage negative feelings toward patients who decline treatment or who are chronic abusers.     

Modelling of a thermomechanically coupled forming process based on functional outputs from a finite element analysis and from experimental measurements

In this paper, measurements from experiments and results of a finite element analysis (FEA) are combined in order to compute accurate empirical models for the temperature distribution before a thermomechanically coupled forming process. To accomplish this, Design and Analysis of Computer Experiments (DACE) is used to separately compute models for the measurements and the functional output of the FEA. Based on a hierarchical approach, a combined model of the process is computed. In this combined modelling approach, the model for the FEA is corrected by taking into account the systematic deviations from the experimental measurements. The large number of observations based on the functional output hinders the direct computation of the DACE models due to the internal inversion of the correlation matrix. Thus, different techniques for identifying a relevant subset of the observations are proposed. The application of the resulting procedure is presented, and a statistical validation of the empirical models is performed.     

Gesture in Instruction: Evidence from Live and Video Lessons

Previous studies have shown that teachers’ gestures are beneficial for student learning. In this research, we investigate whether teachers’ gestures have comparable effects in face-to-face live instruction and video-based instruction. We provided sixty-three 7–10 year old students with instruction about mathematical equivalence problems (e.g., 3 + 4 + 5 = __ + 5). Students were assigned to one of four experimental conditions in a 2 × 2 factorial design that varied (1) instruction medium (video vs. live), and (2) instruction modality (speech vs. speech + gesture). There was no main effect of medium: The same amount of learning occurred whether instruction was done live or on video. There was a main effect of modality: Speech instruction accompanied by gesture resulted in significantly more learning and transfer than instruction conveyed through speech only. Gesture’s effect on instruction was stronger for video instruction than live instruction. These findings suggest that there may be a limit to gesture’s role in communication that results in student learning.     

Enhanced adaptive CUSUM charts for process mean

A statistical quality control chart is an important tool of the statistical process control, which is widely used to control and monitor a production process. The CUSUM chart is designed to detect a specific shift, provided that the shift size is known in advance. In practice, however, shift sizes are rarely known. It is then customary to use an adaptive CUSUM chart, which can effectively detect a range of shift sizes. In this paper, we enhance the sensitivities of the improved adaptive CUSUM mean charts using an auxiliary-information-based (AIB) mean estimator. The run length performances of the proposed charts are compared with those of the AIB adaptive and non-adaptive CUSUM charts in terms of the average run length (ARL), extra quadratic loss, and integral relative ARL. These run length comparisons reveal that the proposed charts are more sensitive than the existing charts when detecting different kinds of shift in the process mean. An example is given to demonstrate the implementation of existing and proposed charts.     

Continuities in Size of Place Preferences in the United States, 1972–19921

Abstract The directions of net migration and population redistribution in the U.S. have switched from nonmetropolitan deconcentration during the 1970s, to metropolitan concentration during the 1980s, and back to deconcentration once again in the early 1990s. The complex causes of these distribution shifts are thought to involve both structural reconfigurations of economic activities that affect the location of opportunities and residential preferences that are tied more closely to amenities and quality of life considerations. This paper uses comparable data from three representative sample surveys of the U.S. population to update and extend earlier research on the preferential basis of redistribution trends. Our analysis does not support the view that shifts in the direction of residential preferences during 1972–1992 tend to coincide with shifts in metropolitan-nonmetropolitan net migration and population redistribution. Rather, a consistent finding across all three surveys is that most people prefer their current residence type, and those who do not are almost twice as likely to prefer lower rather than higher density settings. These findings support the importance of preferences to explanations of recent population trends, but these preferences are not in isolation from the economic contexts in which they occur.     

Two-Stage Cluster Sampling with Ranked Set Sampling in the Secondary Sampling Frame

Motivated by a real-life problem, we develop a Two-Stage Cluster Sampling with Ranked Set Sampling (TSCRSS) design in the second stage for which we derive an unbiased estimator of population mean and its variance. An unbiased estimator of the variance of mean estimator is also derived. It is proved that the TSCRSS is more efficient—in the sense of having smaller variance—than the conventional two-stage cluster simple random sampling in which the second-stage sampling is with replacement. Using a simulation study on a real-life population, we show that the TSCRSS is more efficient than the conventional two-stage cluster sampling when simple random sampling without replacement is used in both stages.     

Mean and cell-mean imputation resulting in the use of a semicontinuous distribution and a mixture of semicontinuous distributions

Zero-inflated models are commonly used for modeling count and continuous data with extra zeros. Inflations at one point or two points apart from zero for modeling continuous data have been discussed less than that of zero inflation. In this article, inflation at an arbitrary point α as a semicontinuous distribution is presented and the mean imputation for a continuous response is discussed as a cause of having semicontinuous data. Also, inflation at two points and generally at k arbitrary points and their relation to cell-mean imputation in the mixture of continuous distributions are studied. To analyze the imputed data, a mixture of semicontinuous distributions is used. The effects of covariates on the dependent variable in a mixture of k semicontinuous distributions with inflation at k points are also investigated. In order to find the parameter estimates, the method of expectation–maximization (EM) algorithm is used. In a real data of Iranian Households Income and Expenditure Survey (IHIES), it is shown how to obtain a proper estimate of the population variance when continuous missing at random responses are mean imputed.     

The Impact of Paternity and Marital Status on Low Birth Weight and Preterm Births

In the United States the number of births to unmarried mothers is at a record high. Although being unmarried is a significant risk factor for low birth weight and preterm births, paternal presence may have a protective effect. In addition to marital status, paternity may be a proxy measure for paternal support. Virginia birth registry data were analyzed to investigate the effect of marital and paternity status on low birth weight and preterm births. Findings from this study show that women who reported being unmarried and with no paternity status were 1.6 (odds ratio = 1.57, 95% confidence interval = 1.41–1.75) and 1.4 (odds ratio = 1.39, 95% confidence interval = 1.21–1.61) times more likely to have preterm low birth weight and term low birth weight babies, respectively. Being unmarried and lack of established paternity appear to be significantly correlated with and may be important risk factors for preterm and low birth weight deliveries. Health care professionals should be aware of the potential role of paternal presence and marital status may play with respect to preterm births and low birth weight.     

Does gold act as a safe haven against exchange rate fluctuations? The case of Pakistan rupee

Investors often look for a refuge to avoid undesirable exposures to risk during period of extreme downturns in currency returns. We investigate daily gold and rupee exchange rates depreciation against set of currencies over the period of 1992–2015. Using wavelets at multiple time horizons; we find that gold act as a consistent short run hedge against exchange rate hence validating the exchange rate destruction hypothesis. This finding is helpful for speculators in their decision making while taking long and short positions accordingly. This finding suggests that central bank also need to keep other safe haven assets in reserves because the hedging ability of gold is only limited to short run. Further, the role of gold in providing protection against currency risks is also confirmed using quantile regression. These results assist portfolio managers and governments in formulating effectual diversification strategy for preserving investment portfolio during extreme event condition. Our results also suggest that gold has a lead relationship with exchange rate; however, this relationship switches over specific time intervals. This finding is of major concern for policy makers in determining the extent of stabilization in gold prices to bring consistency to exchange rate. Finally, the Granger coherence coefficients confirm that the strength of the causal relationship varies across over all frequencies. These conclusions have important implications for policy makers, economic analysts, portfolio managers and institutional investors.