Harry J. Khamis | |
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Occupation(s) | Biostatistician, academic, consultant, and author |
Academic background | |
Education | BS., Mathematics MS., Mathematics PhD., Statistics |
Alma mater | Santa Clara University Virginia Polytechnic Institute & State University |
Thesis | Log-linear Model Analysis of the Association Between Disease and Genotype |
Academic work | |
Institutions | Wright State University;Dayton,Ohio Uppsala University,Uppsala,Sweden |
Harry J. Khamis is a biostatistician,academic,consultant and author. He is the Emeritus Director of the Statistical Consulting Center and an Emeritus Professor in the Department of Mathematics and Statistics and the Department of Community Health at the Boonshoft School of Medicine at Wright State University. [1]
Khamis is most known for his research in statistical methodology,with a particular focus on categorical response models,goodness of fit tests,geometric probability,and the Cox regression model. He has co-authored a book titled Applied Calculus for Students in the Biosciences and is the author of The Association Graph and the Multigraph for Loglinear Models. [2]
Khamis is a Fellow of the American Statistical Association. [3]
Khamis obtained his Bachelor of Science in mathematics from Santa Clara University in 1974,his Master of Science in mathematics in 1976,and his Doctor of Philosophy in Statistics in 1980,both from Virginia Polytechnic Institute &State University. [4]
Khamis began his career in 1980 as an assistant professor at the Department of Mathematics and Statistics at Wright State University. In 1986,he was appointed as an Associate Professor there and concurrently served as an associate professor in the Department of Community Health from 1990 to 1993. From 1994 to 2015,he held a joint appointment as a professor in the Department of Mathematics and Statistics and the Department of Community Health at the Boonshoft School of Medicine. Since his retirement in 2015,he has been serving as Emeritus Professor at the Department of Mathematics and Statistics and the Department of Community Health in the Boonshoft School of Medicine at Wright State University. [1]
Khamis was the associate director of the Statistical Consulting Center from 1989 to 1993 and was appointed as the Director from 1993 to 2015 at Wright State University. Since 2015,he has been holding an appointment as the Emeritus Director of the Statistical Consulting Center within the same institution. [1]
Khamis has authored or co-authored over 100 peer-reviewed publications spanning the areas of health and medical statistics and statistical methodology,including categorical response models,goodness of fit tests,survival analysis,and geometric probability. In addition,he has given over 120 technical talks/seminars all over the U.S. and in 10 other countries.
Collaborating with A.F. Roche,Khamis developed the Khamis-Roche Stature Prediction Model used in predicting adult stature in white American children without using skeletal age. It was found that the method can predict adult stature with only a slight decrease in accuracy and reliability compared to methods using skeletal age. [5] Relatedly,his research validated the variations of the RWT prediction model to estimate adult stature in Caucasian Americans,recommending the multivariate cubic spline smoothing [MCS2(1)] method for improved accuracy and reliability. [6]
In collaborative research on BMI and obesity screening in 1996,it was discovered that BMI is an uncertain indicator of obesity,and specific cut-off values of 25 kg/m2 for men and 23 kg/m2 for women were recommended to enhance obesity screening accuracy by considering body composition. [7] As another example,in collaboration with ophthalmologist John Bullock et al. in 2011,the cause of the Fusarium Keratitis epidemic of 2004-6 was discovered;it was also determined that the epidemic could have been declared several months sooner than the actual declaration. [8]
Khamis' research has contributed to the increased statistical power of the classic Kolmogorov-Smirnov test by introducing a delta in the empirical distribution function. The new test maintained test size and increased power by up to ten percentage points. He then determined that the two-stage delta-corrected test was uniformly more powerful than the classical test. [9]
In collaboration with graph theorist Terry McKee,Khamis developed a methodology for analyzing and interpreting loglinear models using the generator multigraph. This led to a more facile way of analyzing and interpreting loglinear models. In particular,it enables faster and easier ways of identifying decomposable loglinear models,identifying independencies and conditional independencies,and factoring the joint probability in decomposable loglinear models. [2]
Khamis solved a number of variations of the historically classical Buffon's Needle Problem (1733). One unsolved problem was:what is the probability that a needle randomly tossed onto a set of concentric circles will cross a circumference? This problem was solved by him in 1987. [10]
In statistics,the Kolmogorov–Smirnov test is a nonparametric test of the equality of continuous,one-dimensional probability distributions that can be used to test whether a sample came from a given reference probability distribution,or to test whether two samples came from the same distribution. Intuitively,the test provides a method to qualitatively answer the question "How likely is it that we would see a collection of samples like this if they were drawn from that probability distribution?" or,in the second case,"How likely is it that we would see two sets of samples like this if they were drawn from the same probability distribution?". It is named after Andrey Kolmogorov and Nikolai Smirnov.
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Andrey Nikolaevich Kolmogorov was a Soviet mathematician who contributed to the mathematics of probability theory,topology,intuitionistic logic,turbulence,classical mechanics,algorithmic information theory and computational complexity.
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Minimum message length (MML) is a Bayesian information-theoretic method for statistical model comparison and selection. It provides a formal information theory restatement of Occam's Razor:even when models are equal in their measure of fit-accuracy to the observed data,the one generating the most concise explanation of data is more likely to be correct. MML was invented by Chris Wallace,first appearing in the seminal paper "An information measure for classification". MML is intended not just as a theoretical construct,but as a technique that may be deployed in practice. It differs from the related concept of Kolmogorov complexity in that it does not require use of a Turing-complete language to model data.
In mathematics,integral geometry is the theory of measures on a geometrical space invariant under the symmetry group of that space. In more recent times,the meaning has been broadened to include a view of invariant transformations from the space of functions on one geometrical space to the space of functions on another geometrical space. Such transformations often take the form of integral transforms such as the Radon transform and its generalizations.
Per Erik Rutger Martin-Löf is a Swedish logician,philosopher,and mathematical statistician. He is internationally renowned for his work on the foundations of probability,statistics,mathematical logic,and computer science. Since the late 1970s,Martin-Löf's publications have been mainly in logic. In philosophical logic,Martin-Löf has wrestled with the philosophy of logical consequence and judgment,partly inspired by the work of Brentano,Frege,and Husserl. In mathematical logic,Martin-Löf has been active in developing intuitionistic type theory as a constructive foundation of mathematics;Martin-Löf's work on type theory has influenced computer science.
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The Shapiro–Wilk test is a test of normality. It was published in 1965 by Samuel Sanford Shapiro and Martin Wilk.
In statistics,normality tests are used to determine if a data set is well-modeled by a normal distribution and to compute how likely it is for a random variable underlying the data set to be normally distributed.
In 1973,Andrey Kolmogorov proposed a non-probabilistic approach to statistics and model selection. Let each datum be a finite binary string and a model be a finite set of binary strings. Consider model classes consisting of models of given maximal Kolmogorov complexity. The Kolmogorov structure function of an individual data string expresses the relation between the complexity level constraint on a model class and the least log-cardinality of a model in the class containing the data. The structure function determines all stochastic properties of the individual data string:for every constrained model class it determines the individual best-fitting model in the class irrespective of whether the true model is in the model class considered or not. In the classical case we talk about a set of data with a probability distribution,and the properties are those of the expectations. In contrast,here we deal with individual data strings and the properties of the individual string focused on. In this setting,a property holds with certainty rather than with high probability as in the classical case. The Kolmogorov structure function precisely quantifies the goodness-of-fit of an individual model with respect to individual data.
The following is a timeline of probability and statistics.
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This page lists articles related to probability theory. In particular,it lists many articles corresponding to specific probability distributions. Such articles are marked here by a code of the form (X:Y),which refers to number of random variables involved and the type of the distribution. For example (2:DC) indicates a distribution with two random variables,discrete or continuous. Other codes are just abbreviations for topics. The list of codes can be found in the table of contents.
Nikolai Vasilyevich Smirnov was a Soviet Russian mathematician noted for his work in various fields including probability theory and statistics.