This paper discusses proportional odds model and similarity on the construction of Traditional Chinese Medicine (TCM) chronic gastritis syndrome model. The syndromes explain the true relationships among a set of symptoms, which can be characterized by marginal probabilities and conditional probabilities. The former represents the distribution of levels of the syndrome across the symptoms. The l...

Segmentation of perivascular spaces (PVS) from brain magnetic resonance images (MRI) is important for understanding the brain’s lymphatic system and its relationship with neurological diseases. The Frangi filter might be a valuable tool for this purpose. However, its parameters need to be adjusted in response to the variability in scanner’s parameters and study protocols. Knowing the neuroradio...

In this document we describe the Mixture EFA model estimated in Mplus. Four types of dependent variables are possible in this model: normally distributed, ordered categorical with logit or probit link, Poisson distributed with the exponential link function, and censored variables. Inflation is not available for the Censored and Poisson variables. Suppose that we estimate a K class model with M ...

Title: WEATHER IMPACT ON ROAD ACCIDENT SEVERITY IN MARYLAND YUE LIU, M.S. in Civil and Environmental Engineering, 2013 Directed By: Professor and Chair Ali Haghani, Department of Civil and Environmental Engineering This study was conducted to analyze and quantify the impact of weather factors on road accident severity, based on Maryland accident data during 2007-2010. In order to find a better ...

Despite the ordinal nature of Self-Rated Health (SRH) variable, logistic regression models or regression models have been used without adequate justification for these applications. It is shown that ordered-logit regression model is the appropriate statistical strategy to estimate SRH, whereas the Ordinary LeastSquares model leads to biased conclusions.

This paper studies the effects of English proficiency on employment of U.S. foreign-born immigrants, using data from the 2001 American Community Survey (ACS). It shows that English proficiency plays an important role in immigrants’ employment and its effects on employment patterns across genders are different. Probit regressions show that immigrants with a higher level of English proficiency ar...

Work zones are critical parts of the transportation infrastructure renewal process consisting of rehabilitation of roadways, maintenance, and utility work. Given the specific nature of a work zone (complex arrangements of traffic control devices and signs, narrow lanes, duration) a number of crashes occur with varying severities involving different vehicle sizes. In this paper we attempt to inv...

It has been previously argued that there is substantial evidence that lame-duck Republican members of Congress were less supportive of the impeachment of Bill Clinton than their colleagues who returned in the 106th Congress. I show that this conclusion—based on a marginally-significant interaction term—is actually the result of two statistical artifacts: the choice of estimator used, and the in...