Browsing by Subject "R"
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Item Applying Classification and Regression Trees to manage financial risk(2012-05) Martin, Stephen Fredrick; Scott, James Gordon; Carvalho, Carlos M.; Marti, Nathan C.This goal of this project is to develop a set of business rules to mitigate risk related to a specific financial decision within the prepaid debit card industry. Under certain circumstances issuers of prepaid debit cards may need to decide if funds on hold can be released early for use by card holders prior to the final transaction settlement. After a brief introduction to the prepaid card industry and the financial risk associated with the early release of funds on hold, the paper presents the motivation to apply the CART (Classification and Regression Trees) method. The paper provides a tutorial of the CART algorithms formally developed by Breiman, Friedman, Olshen and Stone in the monograph Classification and Regression Trees (1984), as well as, a detailed explanation of the R programming code to implement the RPART function. (Therneau 2010) Special attention is given to parameter selection and the process of finding an optimal solution that balances complexity against predictive classification accuracy when measured against an independent data set through a cross validation process. Lastly, the paper presents an analysis of the financial risk mitigation based on the resulting business rules.Item Influences of Personal Information, Public Information, and Extra-pair Paternity on Breeding Site Fidelity in a Songbird(2012-10-19) Campomizzi, Andrew JamesI investigated the role of extra-pair paternity on use of public information and the interaction between public information and personal information for patch fidelity decisions. It is unknown if songbirds use public information about the number of conspecific fledglings for patch fidelity decisions when extra-pair paternity is uncommon. I tested if probability of patch fidelity was associated with (1) number of fledglings in adjacent territories (public information), and (2) number of fledglings raised with a social mate (personal information). I used logistic regression to predict probability of patch fidelity of males and females based on the 2 uncorrelated predictor variables (Spearman?s rank correlation, S = 21895.28, n = 50, P = 0.723, r = ?0.051). I monitored patch fidelity of 107 territories, counted the number of fledglings in each territory, and assessed parentage of 102 young from 36 nests for white-eyed vireos (Vireo griseus) from 2008?2010 in a 100 ha patch of woodland in central Texas, USA. I excluded the social male as the father of 3 of the 102 young and did not exclude any of the social females as the mother with parentage analysis using 6 microsatellite loci. The number of fledglings in adjacent territories was not a good predictor of probability of patch fidelity for males (beta 1 = 0.166, df = 35, P = 0.247, Nagelkerke?s R2 = 0.054) or females (beta 1 = 0.121, df = 17, P = 0.670, Nagelkerke?s R2 = 0.016). The number of fledglings raised with a social mate was also not a good predictor of probability of patch fidelity for males (beta 1 = ?0.296, df = 43, P = 0.360, Nagelkerke?s R2 = 0.029), whereas it was a good predictor for females (beta 1 = 1.281, df = 21, P = 0.048, Nagelkerke?s R2 = 0.409). The dominant ecological concepts for explaining site fidelity in songbirds, win-stay lose-switch (based on personal reproductive success with a social mate) and public information, did not predict probability of patch fidelity well for male white-eyed vireos. The win-stay lose-switch model, but not public information was a good predictor of probability of patch fidelity for females. My results suggest that use of public information may depend on frequency of extra-pair paternity. Males may primarily use other information for patch fidelity decisions beyond reproductive success of conspecifics for patch fidelity decisions in some circumstances. My results support the need to ensure high levels of nesting success for females to return and maintain populations in areas managed for breeding songbirds for conservation efforts to be successful.