Applied Statistics

Conducting Multilevel Analyses In Medical Education

by Gazi Islam

Biogeography of fruit bats in Southeast Asia. Les S. Hall, Gordon G. Grigg, Craig Moritz, Besar Ketol, Isa Sait, Wahab Marni and M.T. Abdullah.

by M.T. Abdullah, PhD

Should read Abdullah (2003).

We studied on the biogeography and diversity of fruit bats in Southeast Asia, from Borneo to Asian Mainland.The... more We studied on the biogeography and diversity of fruit bats in Southeast Asia, from Borneo to Asian Mainland.The patterns of distribution of distribution, diversity and abundance are related to ecological and biogeographical factors and possible past Pleistocene events.

Les S. Hall, Gordon G. Grigg, Craig Moritz, Besar Ketol, Isa Sait, Wahab Marni and M.T. Abdullah. 2004. Sarawak Museum Journal 81: 191-284.

A morphometric analysis of Rhinolophus species complex. 2008.

by M.T. Abdullah, PhD

DFA and CVA analyses were used to differentiate Malaysian Rhinolophus species complex. DFA and CVA analyses were used to differentiate Malaysian Rhinolophus species complex.

Morphometrical Variations of Malaysian Hipposideros Species. 2012

by M.T. Abdullah, PhD

Read Vijaya et al (2012)

A study on the morphometrical variations among four Malaysian Hipposideros species was conducted using voucher... more A study on the morphometrical variations among four Malaysian Hipposideros species was conducted using voucher specimens deposited in Universiti Malaysia Sarawak (UNIMAS) Zoological Museum and the Department of Widlife and National Park (DWNP) Kuala Lumpur. Twenty two individuals from four species of Hipposideros ater, H. bicolor, H. cineraceus and H. dyacorum were morphologically measured, in which a total of 27 linear parameters of body, skull and dentals of each were appropriately recorded. The statistical data were later subjected to discriminant function analysis (DFA) and canonical variate analysis (CVA) using SPSS version 15.0 and unweighted pair-group method average (UPGMA) cluster analysis using Minitab version 14.4. The highest character loadings observed in Function l, Function 2 and Function 3 were the forearm length (FA), the third digit second phalanx length (D3P2L) and the palatal length (PL) with standardised canonical discriminant function coefficient values of 21.910, 5.770 and 5.095, respectively. These three characters were identified as the best diagnostic features for discriminating these closely related species of Hipposideros. Hence, this morphometric approach could be a promising tool as an alternative to the molecular
DNA analysis for identification of Chiroptera species.

A Predictive Model to Differentiate the Fruit Bats Cynopterus brachyotis and C. cf. brachyotis Forest (Chiroptera: Pteropodidae) from Malaysia Using Multivariate Analysis. 2012

by M.T. Abdullah, PhD

Read also Abdullah (2003)

Field discrimination of Cynopterus brachyotis and C. cf. brachyotis Forest (as designated by Francis 2008) in southern... more Field discrimination of Cynopterus brachyotis and C. cf. brachyotis Forest (as designated by Francis 2008) in southern Thailand, Peninsular Malaysia, and Borneo is problematic. These 2 forms are sympatric in this region but are confined to different habitat types: C. brachyotis inhabits open habitats, orchards, and agricultural areas, while C. cf. brachyotis Forest is confined to primary and old secondary forests. In this study, we attempted to develop prediction models to identify both C. brachyotis and C. cf. brachyotis Forest in this region based on multivariate statistics. Two predictive models were generated using a canonical discriminant function, and it was found that 5 characters can be used to accurately identify museum vouchers of C. brachyotis and C. cf. brachyotis Forest. Four characters are needed for field identification of these 2 forms of Cynopterus in southern Thailand, Peninsular Malaysia, and Borneo. A review of the current taxonomy and classification indicated that there is a need to describe the 6 existing forms of the C. brachyotis complex in the Indo-Malayan region. This will aid conservationists, field ecologists, and taxonomists in taxonomic- and conservation-related decisions about this species complex.

Assessing the probability of detection of horizontal gene transfer events in bacterial populations

by Jeffrey Townsend

Wallet and Share of Wallet Estimation: A Flexible Methodology

by Shira Guil Witelson

Published by NESUG 2010 and SAS in 2012

In this paper, we will demonstrate how Wallet and Share of Wallet estimation, widely used in the credit card industry... more In this paper, we will demonstrate how Wallet and Share of Wallet estimation, widely used in the credit card industry for marketing and sales strategy, can be applied in a range of industries. The methodology presented consists of a series of steps, beginning with primary research, and progressing to the use of SAS-enabled unsupervised learning method, predictive modeling and statistical test techniques. The result is a flexible means for estimating the most realistically attainable Wallet of a customer and thereby calculating the customer’s Share of Wallet.
Definitions:
Internal Spend: The dollar amount the customer spends on the company’s products and services.
External Spend: The dollar amount the customer spends on other providers’ products and services.
Wallet: The Total Spend (Internal and External) made by the customer with the company and other providers, so long as the company provides one of the services purchased.

Predicting success, excellence, and retention from students' early course performance: progress results from a data-mining-based decision support system in a first year tertiary education programme

by Peter Mellalieu

Mellalieu, P. J. (2011). Predicting success, excellence, and retention from students’ early course performance: progress results from a data-mining-based decision support system in a first year tertiary education programme. XXIX International Conference of the International Council for Higher Education (Vol. 24). Presented at the Innovation and Development in Higher Education, Miami/Ft Lauderdale: International Council for Higher Education. Retrieved from http://web.mac.com/petermellalieu/Teacher/Examples/Entries/2011/6/30_MELLALIEU_2011_Predicting_success_ICIE_abstract_proposal.html

Higher educational institutions are focussing increased attention on identifying which students are likely to succeed... more Higher educational institutions are focussing increased attention on identifying which students are likely to succeed - or fail - in their tertiary studies. Culver (2010, 2011), for instance, reports on the business case for, and services provided by the Noel-Levitz consultancy for improving institutional retention in North America. In New Zealand, government funding for higher education is increasingly being redirected towards a focus on outputs (such as course completions) rather than inputs (student enrollments) (Ministry of Education, 2010).


Anticipating this context, I constructed a prototype Decision Support System (ReXS) to provide my students the means to predict their personal academic success and final grade as they progressed through a first-year (freshman) course ‘Innovation and Entrepreneurship’. Data mining of previous semesters’ course results identified the crucial importance of a student's ability to write formal academic English as demonstrated in a written case study assignment. Several students’ immediate reaction to a presentation introducing them to ReXS was unexpectedly enthusiastic and they became ‘early adopter’ users. ‘Late adopter’ users of ReXS also gained confidence in identifying the degree of effort they needed to apply to complete the course succesfully through their Final Test.


Whilst ReXS is a bespoke solution tailored to the particular assessment regime of a particular course, I believe the principles of its design and construction can be applied to any assessed course in higher education. Certainly, my students indicated they would welcome widespread adoption of the approach in other courses in their study program. The presentation provides an opportunity to discuss: Reactions from the student users of ReXS; Illustrations of the predictions made by the ReXS; How the principles underlying the Decision Support System can be extended to other courses; Opportunities for improving the utility of ReXS for students, academic, and administrative staff.

A Bayesian approach for inferring neuronal connectivity from calcium fluorescent imaging data

by Joshua Vogelstein

Shuffled Graph Classification: Theory and Connectome Applications

by Joshua Vogelstein

Graph Classification using Signal Subgraphs: Applications in Statistical Connectomics

by Joshua Vogelstein

Optimizing the quantity/quality trade-off in connectome inference

by Joshua Vogelstein

EstCRM: An R package for Samejima's Continuous IRT Model.

by Cengiz Zopluoglu

http://apm.sagepub.com/content/current

EstCRM: An R Package for Samejima’s Continuous IRT Model, Applied Psychological Measurement, March 2012, 36, 149-150

Continuous Response Model (CRM) is an IRT model developed for continuous outcomes. CRM is not commonly used in... more Continuous Response Model (CRM) is an IRT model developed for continuous outcomes. CRM is not commonly used in practice although it is as old as the other well known and popular binary and polytomous IRT models. This may be due to the lack of an accessible software to estimate the model parameters. The R package, EstCRM, was developed to estimate the model parameters for the CRM.

Bumper Paint Damage in Low Speed Impacts

by Lee D. Han

SAE Technical Paper 2007, DOI: 10.4271/2007-01-0728
with Bryce Anderson, John Hungerford, Tyler Kress, Steve Richards, and Ken Kirby

This paper presents a methodology to determine the approximate closing speed of a striking vehicle and re-sultant... more This paper presents a methodology to determine the approximate closing speed of a striking vehicle and re-sultant delta-v of the struck vehicle in low speed collinear rear impacts through analysis of the paint damage pat-tern evident on the struck vehicle’s rear bumper. This methodology is only applicable to collisions between vehicles that possess painted flexible plastic foam support-ed bumpers. Five impacts at each of 1.12 m/s, 1.79 m/s, and 2.69 m/s target speeds and three impacts at 3.58 m/s target speeds using freshly painted bumpers were conducted to provide the foundation for this methodology.

The use of powdered guide coat is introduced to contrast the damage pattern on the bumper of the struck vehicle. A measurement of contact paint damage area is obtained and that damage area is then correlated to a closing velocity between the two vehicles. Empirically measured coefficients of restitution and calculated quantities of energy absorbed are also presented for each impact.

The relationship between struck vehicle paint damage area and impact speed was found to be strongly statistically significant (p < 0.001). A positive correlation was found between struck vehicle bumper paint damage and struck vehicle delta-v, with an r-value of 0.978 at a statistically significant level (p < 0.001).

Latent variable modeling of disability in people aged 65 or more

by Paolo Eusebi

Montanari GE, Ranalli MG and Eusebi P
Statistical Methods & Applications 20 (1), 49-63, DOI:10.1007/s10260-010-0148-6

Realistic Modeling of Local Network Traffic

by Stefan Karpinski

The Polish LFS: A Rotating Panel with Attrition

by Francesco Pastore

Co-authored with M. Socha.
Ekonomia Journal, 2004, 15(3): 3-24.

Started in May 1992, the Polish Labour Force Survey (PLFS) is one of the most important data sources to study the... more Started in May 1992, the Polish Labour Force Survey (PLFS) is one of the most important data sources to study the labour market dynamics in Eastern Europe. It is a typical rotating panel with a 2-2-2 rotation scheme. Similar to any other longitudinal survey, panel attrition, also due to measurement errors, is one the main shortcomings of the PLFS. This paper contributes to the analysis of panel attrition in longitudinal survey data in three ways. First, it shows that albeit limited at about 6.5%, attrition in the PLFS is systematic. Second, it shows that panel attrition can cause biased estimates of transitions in the labour market, giving the fake impression of low numerical flexibility. Third, it studies the determinants of attrition. A logistic estimate of the probability of panel selection across the November 1995 and November 1996 rounds of the survey shows that the probability of failing to match consecutive observations is higher among young highly educated men residing in the lowest unemployment regions of the country. Further problems might arise because of unobservables. This is suggestive of the need to take the due caveats when analysing information coming from rotating panels.

Using mixed models to smooth regression coefficients corresponding to inter-correlated explanatory variables: an application to weather covariates

by Michelle Sims

In: Francis, A.R., Matawie, K.M., Oshlack, A. and Smyth, G.K., eds. Statistical Solutions to Modern Problems. Proceedings of the 20th International Workshop on Statistical Modelling. Statistical Modelling Society, p. 5.

Identifying when weather influences life‐history traits of grazing herbivores

by Michelle Sims

Journal of Animal Ecology, 2007

1.There is increasing evidence that density-independent weather effects influence life-history traits and hence the... more 1.There is increasing evidence that density-independent weather effects influence life-history traits and hence the dynamics of populations of animals. Here, we present a novel statistical approach to estimate when such influences are strongest. The method is demonstrated by analyses investigating the timing of the influence of weather on the birth weight of sheep and deer.

2.The statistical technique allowed for the pattern of temporal correlation in the weather data enabling the effects of weather in many fine-scale time intervals to be investigated simultaneously. Thus, while previous studies have typically considered weather averaged across a single broad time interval during pregnancy, our approach enabled examination simultaneously of the relationships with weekly and fortnightly averages throughout the whole of pregnancy.

3.We detected a positive effect of temperature on the birth weight of deer, which is strongest in late pregnancy (mid-March to mid-April), and a negative effect of rainfall on the birthweight of sheep, which is strongest during mid-pregnancy (late January to early February). The possible mechanisms underlying these weather–birth weight relationships are discussed.

4.This study enhances our insight into the pattern of the timing of influence of weather on early development. The method is of much more general application and could provide valuable insights in other areas of ecology in which sequences of intercorrelated explanatory variables have been collected in space or in time.

Incorporating variance uncertainty into a power analysis of monitoring designs

by Michelle Sims

Journal of Agricultural, Biological and Environmental Statistics, 2007

Power calculations usually assume that the components of the population variance are known, but it is frequently the... more Power calculations usually assume that the components of the population variance are known, but it is frequently the case that they are estimated using data from a pilot study. Imprecision in the estimates is then ignored and a single value for power is generated. We present a method that incorporates the error in the estimates of any number of variance components into the power calculations. We show that, by sampling values for the variance components from the residual likelihood function of the pilot data, our method can approximate the distribution of powers expected given the uncertainty in the variance components. Alternative summary measures of power can then be derived: we strongly recommend treating a minimum acceptable power as a quality standard and summarizing power in terms of the probability that this quality standard is attained. The method is illustrated by application to counts of common guillemots (Uria aalge ) on the Isle of May in Scotland to assess the power of detecting long-term trends in abundance using a model for random variation with seven parameters.