The treatment of ties in non-parametric tests.

Thesis (M.A.)--Boston UniversityIn most of the non-parametric methods, only a few general assumptions are made concerning the underlying distribution of the population from which a certain sample is drawn. One of the most frequent of these assumptions is that of continuity, i.e., that the population from which the sample is drawn possesses a continuous distribution, and, therefore, the probability of two or more equal observations is zero. Actually, however, due to limitation of measurement, experimental data are such that they must usually be regarded as coming from discontinuous distributions and equal observations will occur. When this is the case, one speaks of the occurrence of "tied" observations, or simply "ties", in the data. [TRUNCATED] In this paper are discussed the dif£erent solutions that various statisticians have suggested in treating tied observations when applying the following non-parametric tests: (1) the sign test, (2) the Wilcoxon (Mann-Whitney) test, (3) the Wald-Wolfowitz Runs test, (4) The Moses test, (5) the Kruskal-Wallis test, (6) Kendall's rank correlation coefficient test, and {7) Kendall's coefficient of concordance test. It is found that most of the statisticians recommend the mid-rank method of treating ties

Modeling the International-Trade Network: A Gravity Approach

This paper investigates whether the gravity model (GM) can explain the statistical properties of the International Trade Network (ITN). We fit data on international-trade flows with a GM specification using alternative fitting techniques and we employ GM estimates to build a weighted predicted ITN, whose topological properties are compared to observed ones. Furthermore, we propose an estimation strategy to predict the binary ITN with a GM. We find that the GM successfully replicates the weighted-network structure of the ITN, only if one fixes its binary architecture equal to the observed one. Conversely, the GM performs very badly when asked to predict the presence of a link, or the level of the trade flow it carries, whenever the binary structure must be simultaneously estimated

Information sheet 25: Elodea nutallii, Nuttall's Pondweed

Information sheet on control of Elodea specie

Modeling the International-Trade Network: A Gravity Approach

This paper investigates whether the gravity model (GM) can explain the statistical properties of the International Trade Network (ITN). We fit data on international-trade flows with a GM specification using alternative fitting techniques and we employ GM estimates to build a weighted predicted ITN, whose topological properties are compared to observed ones. Furthermore, we propose an estimation strategy to predict the binary ITN with a GM. We find that the GM successfully replicates the weighted-network structure of the ITN, only if one fixes its binary architecture equal to the observed one. Conversely, the GM performs very badly when asked to predict the presence of a link, or the level of the trade flow it carries, whenever the binary structure must be simultaneously estimated.International Trade Network; Gravity Equation; Weighted Network Analysis; Topological Properties; Econophysics

Closed Meetings & Advisors

Under Article II Meetings of the ASWC By Laws, a subsection K be added to read: K. To close a meeting, a motion must be presented and receive a 2/3 majority of those voting and present. Unless otherwise specified, the administrative and faculty advisor of the ASWC will exit the room

Planetary Protection Requirements for Robotic and Human Missions

Planetary Protection involves the development and implementation of policies and requirements to protect solar system bodies from forward and backward contamination during human or robotic space missions. As stipulated by the United Nations Outer Space Treaty (Article IX) and interpreted by the Committee on Space Research, over 100 nations abide by the treaty and its objectives. Since the beginning of the space age, NASA has complied with planetary protection requirements across more than 250 robotic and human missions, especially those involving Mars, which is a planet with potentially habitable conditions for microbial life. A sample of past, current, and future missions can serve to illustrate how planetary protection practices have been used to protect Mars regardless of mission target. Since the recent reorganization of NASA’s Office of Planetary Protection to the Office of Safety and Mission Assurance, there is a need for updating websites, revising training materials and courses, and considering how the international policies will apply to commercial missions specifically those with target bodies with potential for microbial life. Goals of this internship project where to gather, summarize, and organize existing materials about planetary protection from the public domain. Another goal was to cover the history of planetary protection by considering how NASA center and partners are supporting planetary protection (lab capabilities, curations, methods, and techniques.) Specifically, the objective of this document and compilation is to provide the Planetary Protection Office with a comprehensive summary of historical and current information to be used for multiple purposes

Slotting Allowance: an Overlooked Angle in Grocery Retailing

Ever wonder why one product brand enjoys a more prominent shelf location in a particular retail establishment than another brand? Would such arrangement have any impact on the price one pays for a particular product? Answers to these are related to the relatively unexplored business phenomenon known as slotting allowances or fees for store shelf space. Read more about it...slotting allowance, retail market, distribution market, intermediate market, shelf space rental fee, product brand, store shelf space