Harry J. Khamis

Key takeaways

Harry J. Khamis belongs to astronomy; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Harry J. Khamis to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Harry J. Khamis from memory before moving on to harder problems.

Reference excerpt

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. 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. Khamis is a Fellow of the American Statistical Association.

Education 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.

Career 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. 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.

Research 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.

Khamis-Roche stature prediction model 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. 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.

Collaborative medical research 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. 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.

Two-stage delta-corrected kolmogorov-smirnov test 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.

Multigraph representation of hierarchical loglinear models 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.

Geometric probability 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.

Awards and honors 2011 – Professional Statistician (“PStat”), American Statistical Association 2014 – Elected Fellow, American Statistical Association

Bibliography

Books Association Graph and the Multigraph for Loglinear Models (2011) ISBN 9781412972383 Applied Calculus for Students in the Biosciences, Linus Learning

Selected articles Khamiss, H. J. (1983). Log-linear model analysis of the semi-symmetric intraclass contingency table. Communications in Statistics-Theory and Methods, 12(23), 2723–2752. Khamis, H. J. (1987). On Buffon's Needle Problem Using Concentric Circles. Pi Mu Epsilon Journal, 8(6), 368–376. Khamis, H. J. (1988). Contingency table estimation of genetic parameters and disease risks. Statistics in Medicine, 7(5), 591–600. Khamis, H. J., & Roche, A. F. (1994). Predicting adult stature without using skeletal age: the Khamis-Roche method. Pediatrics, 94(4), 504–507. Erratum: Pediatrics 95(3), 457. Khamis, H. J. (2000). The two-stage delta-corrected Kolmogorov-Smirnov test. Journal of Applied Statistics, 27(4), 439–450. Khamis, H. J. (2005). Multigraph modeling. Wiley StatsRef: Statistics Reference Online. Khamis, H. J., & Kepler, M. (2010). Sample size in multiple regression: 20+ 5k. Journal of Applied Statistical Science, 17(4), 505. Khamis, H. J. (2011). The association graph and the multigraph for loglinear models (Vol. 167). Sage Publications.

References

External links Home page Harry J. Khamis at the Mathematics Genealogy Project

Worked examples

Example 1 — a first encounter with Harry J. Khamis

Start with the simplest possible case. Write down what Harry J. Khamis claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In astronomy, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Harry J. Khamis before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Harry J. Khamis ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Harry J. Khamis

In research: Harry J. Khamis appears in astronomy research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Harry J. Khamis in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Harry J. Khamis is common in secondary-school and first-year university syllabi. It links to neighbouring topics Biostatisticians, Living people, Santa Clara University alumni, so understanding it makes those chapters shorter.
In everyday life: Look for Harry J. Khamis outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

How to study Harry J. Khamis in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Harry J. Khamis means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Harry J. Khamis out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Harry J. Khamis in simple terms?

Harry J. Khamis is a biostatistician, academic, consultant and author.

Why does Harry J. Khamis matter?

Because it connects several astronomy ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Harry J. Khamis?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Harry J. Khamis.