Search results for " overdispersion"

showing 3 items of 3 documents

Degree course change and student performance: a mixed-effect approach

2015

This paper focuses on students credits earning speed over time and its determinants, dealing with the huge percentage of students who do not take the degree within the legal duration in the Italian University System. A new indicator for the performance of the student career is proposed on real data, concerning the cohort of students enrolled at a Faculty of the University of Palermo (followed for 7 years). The new indicator highlights a typical zero-inflated distribution and suggests to investigate the effect of the degree course (DC) change on the student career. A mixed-effect model for overdispersed data is considered, with the aim of taking into account the individual variability as wel…

Statistics and ProbabilityMixed modelMotion chart05 social sciences050301 education01 natural sciencesCourse (navigation)Degree (temperature)010104 statistics & probabilityOverdispersionCohortComputingMilieux_COMPUTERSANDEDUCATIONMathematics educationuniversity credits expected years to the graduation overdispersion ZIP model longitudinal data motion chartSettore SECS-S/05 - Statistica Sociale0101 mathematicsStatistics Probability and UncertaintyDuration (project management)PsychologySettore SECS-S/01 - Statistica0503 educationUniversity system
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Estimating the safety performance function for urban unsignalized four-legged one-way intersections in Palermo, Italy

2014

Abstract Starting from consideration that urban intersections are sites with promise for safety and operational improvements, the paper describes the steps taken to develop a crash predictive model for estimating the safety performance of urban unsignalized intersections located in Palermo, Italy. The focus is on unsignalized four-legged one-way intersections widespread in Italian downtowns. The sample considered in the study consist of 92 intersections in Palermo, Italy. For the study were collected crashes occurred in the sites during the years 2006-2012, geometric design and functional characteristics and traffic flow. Results showed that data were overdispersed and NB1 distributed. In o…

overdispersionCrashSample (statistics)safety performance functionsSafety performance functions urban intersection overdispersion correlationTransport engineeringurban intersectionGeometric designGeographyOverdispersionlcsh:TA1-2040correlationSettore ICAR/04 - Strade Ferrovie Ed AeroportiPerformance functionlcsh:Engineering (General). Civil engineering (General)Generalized estimating equationCivil and Structural Engineering
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Challenges in dental statistics: data and modelling

2022

The aim of this work is to present the reflections and proposals derived from the first Workshop of the SISMEC STATDENT working group on statistical methods and applications in dentistry, held in Ancona (Italy) on 28th September 2011. STATDENT began as a forum of comparison and discussion for statisticians working in the field of dental research in order to suggest new and improve existing biostatistical and clinical epidemiological methods. During the meeting, we dealt with very important topics of statistical methodology for the analysis of dental data, covering the analysis of hierarchically structured and over-dispersed data, the issue of calibration and reproducibility, as well as some…

lcsh:R5-920Dental researchbusiness.industryCalibration (statistics)lcsh:Public aspects of medicinelcsh:RA1-1270Epidemiological methodMultilevel modelingExaminer reliabilityField (computer science)ReproducibilityOverdispersionSettore MED/01 - Statistica MedicaSurvey methodologyDmftDmft; Multilevel modeling; Zero-inflation; Overdispersion; Reproducibility; Examiner reliabilityDental EpidemiologyStatisticsMedicinebusinesslcsh:Medicine (General)Zero-inflation
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