Bollinger Bands Thirty Years Later

The goal of this study is to explain and examine the statistical underpinnings of the Bollinger Band methodology. We start off by elucidating the rolling regression time series model and deriving its explicit relationship to Bollinger Bands. Next we illustrate the use of Bollinger Bands in pairs trading and prove the existence of a specific return duration relationship in Bollinger Band pairs trading.Then by viewing the Bollinger Band moving average as an approximation to the random walk plus noise (RWPN) time series model, we develop a pairs trading variant that we call "Fixed Forecast Maximum Duration' Bands" (FFMDPT). Lastly, we conduct pairs trading simulations using SAP and Nikkei index data in order to compare the performance of the variant with Bollinger Bands

Tanzania: Pilot Rural Investment Climate Assessment. Stimulating Nonfarm Microenterprise Growth

Tanzania’s Pilot Rural Investment Climate Assessment (RICA) measures the economic environment of non-farm entrepreneurs. The pilot assessment has three key objectives: it aims to better understand the rural non-farm economy in Tanzania, shed light on rural enterprise dynamics and business constraints, and reflect on areas where government policies are readily directed to help promote rural non-farm enterprise activity. The RICA is based on an analysis of a unique survey data set collected by the National Bureau of Statistics (NBS) during January and March 2005, covering enterprises, households, and communities in all seven geographical zones of the country. Selected findings are: (i) Non-farm activities are an important source of income for approximately 1.4 million rural households, (ii) Tanzanian rural non-farm enterprises differ from their urban counterparts, (iii) the predominant entrepreneurial activity is trading, (iv) labor productivity is typically low, (v) formal enterprises have higher levels of labor productivity than informal, (vi) the rate of new firm creation appears to be lower than in other African countries, and (vii) only a minority of enterprises propels employment growth. The pilot approach call for a careful evaluation of the following recommendations, which presented to stimulate dialogue and future analysis: (i) favorable policies and investments for agriculture play a big role for rural enterprises, (ii) maintaining favorable internal trade policies may therefore be of utmost importance in determining enterprise performance, (iii) microcredit and savings may offer a tool for promoting rural non-farm activity in buoyant rural markets, (iv) easing bottlenecks in rural infrastructure is important, (v) exploring options for better telecommunications via private sector cell phone nodes may be an attractive policy option to stimulate entrepreneurial activities, (vi) continuation of business registration reform and effective implementation at the local level remains a high priority, and (vii) future analysis should address knowledge gaps.Tanzania; rural labor markets; enterprise performance; informal sector

Are Sunk Costs Irrelevant? Evidence from Playing Time in the National Basketball Association

The relevance of sunk costs in decision making is one of the major sources of disagreement between neoclassical economists and behavioral economists. We test the importance of sunk costs by examining the role of a player's draft position on his playing time in the National Basketball Association. Specifically, we ask whether players taken as lottery picks or in the first round of the draft are treated differently from otherwise identical players who are chosen later. We build on previous studies in three ways. First, we study a time period that had a stronger contrast between the financial commitment to first and second-round draft picks. Second, we use a better measure of playing time by accounting fully for the time a player loses to injury, suspension, or other exogenous factor. Finally and most importantly, we use a more sophisticated methodology regression discontinuity to test for whether teams treat lottery picks or first-round picks differently from later picks. Our results find little or no impact of draft round or lottery status on playing time. Hence, our findings strongly support the neoclassical outlook

Food and Mood: Exploring the determinants of food choices and the effects of food consumption on mood among women in Inner London.

Introduction: The aim of this study was to explore the relationship between food and mood against the backdrop of increased mental health and nutrition cognizance within public health and scientific discourses. Mood was defined as encompassing positive or negative affect. Methodology: A constructionist qualitative approach underpinned this study. Convenience sampling in two faith-based settings was utilised for recruiting participants, who were aged 19-80 (median,48) years. In total 22 Christian women were included in the research, eighteen were in focus groups and four were in individual semi structured interviews. All were church-attending women in inner London. A thematic analysis was carried out, resulting in four central themes relating to food choice and food-induced mood states. Findings: Women identified a number of internal and external factors as influencing their food choices and the effect of food intake on their moods. Food choice was influenced by mood; mood was influenced by food choice. Low mood was associated with unhealthy food consumption, apparent addiction to certain foods and overeating. Improved mood was associated with more healthy eating and eating in social and familial settings. Discussion: Findings indicate food and mood are interconnected through a complex web of factors, as women respond to individual, environmental, cultural and social cues. Targeting socio-cultural and environmental influences and developing supportive public health services, via faith-based or community-based institutions could help to support more women in their struggle to manage the food and mood continuum. Successful implementation of health policies that recognise the psychological and social determinants of food choice and the effect of food consumption on mood, is essential, as is as more research into life-cycle causal factors linking food choice to moo

Modern Statistical Methods in Oceanography: A Hierarchical Perspective

Processes in ocean physics, air-sea interaction and ocean biogeochemistry span enormous ranges in spatial and temporal scales, that is, from molecular to planetary and from seconds to millennia. Identifying and implementing sustainable human practices depend critically on our understandings of key aspects of ocean physics and ecology within these scale ranges. The set of all ocean data is distorted such that three- and four-dimensional (i.e., time-dependent) in situ data are very sparse, while observations of surface and upper ocean properties from space-borne platforms have become abundant in the past few decades. Precisions in observations of all types vary as well. In the face of these challenges, the interface between Statistics and Oceanography has proven to be a fruitful area for research and the development of useful models. With the recognition of the key importance of identifying, quantifying and managing uncertainty in data and models of ocean processes, a hierarchical perspective has become increasingly productive. As examples, we review a heterogeneous mix of studies from our own work demonstrating Bayesian hierarchical model applications in ocean physics, air-sea interaction, ocean forecasting and ocean ecosystem models. This review is by no means exhaustive and we have endeavored to identify hierarchical modeling work reported by others across the broad range of ocean-related topics reported in the statistical literature. We conclude by noting relevant ocean-statistics problems on the immediate research horizon, and some technical challenges they pose, for example, in terms of nonlinearity, dimensionality and computing.Comment: Published in at http://dx.doi.org/10.1214/13-STS436 the Statistical Science (http://www.imstat.org/sts/) by the Institute of Mathematical Statistics (http://www.imstat.org

Investigation of seismicity and related effects at NASA Ames-Dryden Flight Research Facility, Computer Center, Edwards, California

This report discusses a geological and seismological investigation of the NASA Ames-Dryden Flight Research Facility site at Edwards, California. Results are presented as seismic design criteria, with design values of the pertinent ground motion parameters, probability of recurrence, and recommended analogous time-history accelerograms with their corresponding spectra. The recommendations apply specifically to the Dryden site and should not be extrapolated to other sites with varying foundation and geologic conditions or different seismic environments

Evaluation of liquid methane storage and transfer problems in supersonic aircraft

Evaluation of liquid methane storage and transfer problems for future supersonic aircraft cryogenic fuel requirement