Department Highlight – Mathematics & Statistics Professor Kimberly Sellers Creates Varied Research Opportunities for Students

If the movie Hidden Figures taught us anything, it is that there are often forces in the background working to make anything possible. Though the study of math and statistics is fundamental, research in these disciplines is not as widely recognized as the other natural sciences like biology, chemistry, or physics. But without it, we would never have been able to send someone to the moon and back. Department of Mathematics and Statistics professor Kimberly Sellers is working to highlight the power of math and statistics for the next generation of researchers, helping Georgetown undergraduates realize that the sky is no longer the limit.

Finding Research

Sellers is a continual advocate for undergraduate research, actively collaborating with students to develop mathematical projects that have real-world applications. Currently, there are several ways that students can become involved in research at Georgetown, though they are not always apparent. There are fellowship opportunities, GUROP, and fairs like the fall Science Research Opportunities Fair hosted by the Georgetown chapter of Psi Chi where students can learn about various labs available to them on campus. Students are even encouraged to speak with professors one-on-one outside of class.

Knowing that there are limited fellowship slots and recognizing that many people are simply unaware of the vast research opportunities in the mathematical sciences, Sellers frequently participates in the fair, consistently coming away with a new cohort of students eager to conduct research.

“I make sure to go to the fair because our students need to know that research experience through the Mathematics and Statistics Department is not only available to graduate students, but for undergraduate students as well,” says Sellers. “I have found that students really want to participate in the work being done by every department; they just don’t know how to go about starting that process. Going to campus events like the fair really makes a difference.”

Real World Applications: Analyzing Gun Violence Statistics

This fair is where Sellers recruited several students currently working with her on research projects. Zev Burton (SFS’22) and Sarah Lalevee (C’22) were interested in working on statistical analyses. After approaching Sellers, they were partnered with Runzhong Xu (C’21) who had independently sought out research opportunities with Sellers.

These three students are collaborating on a statistical analysis project regarding mass gun violence in America. Since beginning their research with Sellers, the trio has presented at two spring undergraduate conferences on Georgetown’s campus where they gain experience presenting their work in different formats (oral or poster presentations).

“I was interested in doing research in some capacity, but I didn’t really know where to start,” says Lalevee. “Zev and I didn’t have a background in statistics, so working with Stephen and Professor Sellers gave us an experience we otherwise would not have had.”

Sellers believes that this type of research is essential for students and hopes that iterations will continue in the future.  

“It can be difficult for students to take what they learn in class and conceptualize it for the real world,” says Sellers. “Projects like this help students understand what they’ve learned, and see how they can apply that knowledge in other fields. I also try to remove intimidation that is associated with research. The notion of writing a thesis or dissertation is so big and overwhelming, I try to remove that sense of intimidation with research and writing.”

Ultimately, the students and Sellers are in the process of publishing a paper with their findings to better articulate the associations that lead to mass shootings in America. Burton, Lalevee, and Xu will have gained real-world experience in statistics and applied mathematics. 

“Besides learning how to apply the theories we learn in class to actual world data, the most important thing I learned through working closely with Professor Sellers, Sarah, and Zev is that conducting research and producing meaningful results require collaborated effort and everyone contributing their unique ideas and knowledge about the subject,”. Says Xu. “How to work together in a productive way and learning from each other can sometimes be the most valuable part of research.”

The students consider this one of the most impactful experiences they have had at Georgetown, and attribute it largely to their professor.

“It’s really difficult for all of us to really articulate how much we have appreciated this experience,” says Burton. “We have grown so much as researchers, as individuals, and it’s all thanks to Professor Sellers.”

Research: An Alternate Extracurricular

Many students are interested in research because they want an experience that differs from other extracurriculars on campus.

“I wasn’t getting as much out of the clubs available to me at Georgetown,” says Sean Melville (C’20). “I really wanted to do something meaningful with more of an academic focus. So, I went to the undergraduate research fair and met with Professor Sellers.”

Melville was partnered with Fanyu Cui (C’20) who also met Sellers at the fair. The two are conducting methodological research to develop a new, flexible time series model for analyzing count data that are observed over time, where the underlying assumptions about the data are more relaxed than in previous works. Cui and Melville describe their work as a “Russian nesting doll” for statistical models that can analyze time series count data. Together, they have collaborated on literature reviews, proofread each other’s work, and informed one another about relevant research in this area.

“Sean and I work together on everything first before going to Professor Sellers,” says Cui. “I wanted to understand what the research process was like and how you start and continue. I am interested in getting my PhD, so this true research experience is really invaluable.”

Melville and Cui are working with Sellers and Professor Ali Arab to publish a paper on their analyses.

Creating Unique Opportunities

Sellers is also eager to help students who approach her outside of structured events.  Students like Stephen Peng (MSB’18) have asked about research opportunities after the first day of class. Though he is currently completing his engineering degree at Columbia as part of Georgetown’s  3-2 Combined Plan joint degree in partnership with the Fu Foundation School of Engineering and Applied Science, Peng worked with Sellers while in the GUROP program to develop another time series model for count data. This project, similar to the one Sellers is completing with Cui and Melville, deals with developing a flexible model for count data that are collected over time.

“A real-world example where this model can be applied is to describe the total number of customers that frequent a store during a day through a statistical model,” says Peng. “Imagine that a store opens and three people come in, but then two leave and then five more enter. What is the total? You might have correctly guessed six, but with larger data sets it becomes more complicated. Stores would be interest to use such analyses to understand the amount of traffic they get through their stores, or (better yet) the number of purchases over time. Our model helps compute data that is hard for humans to keep track of.”

At the International Conference on Statistical Distributions and Applications in October of 2019, Peng presented about their research in an invited session during the conference – a coveted slot usually reserved for academic faculty and other career statisticians. “I was the only undergraduate that spoke, but because of Professor Sellers, I was very prepared,” says Peng.  “I plan to use this experience going forward. In the long term, no matter what I end up doing, I want to work with data and with numbers. This gives me credibility and has taught me a lot about what to do when working with data and developing models.” This work has also been published in the Journal of Time Series Analysis.

Opportunities for All

Sellers is one of many professors who is deeply invested in undergraduates at Georgetown. Inside the Mathematics and Statistics Department and elsewhere, there are numerous ways that students can begin research in an area that interests them. To find out more, check out the research opportunities available to you at Georgetown.

-by Shelby Roller (G’19)