Talks (unless otherwise indicated) are in Davis 301 from 4–5 PM on Mondays. Refreshments begin at 3:30 on the second floor of Davis.
To make sure you get email updates, add yourself to the mathstu (if a student) or mathothers (if not) email groups. Or check the Colby Math&Stats facebook page.
You can see last semester’s schedule.
Naturally rerandomized experiments: The effect of mentors on majors and a power simulation
We examined the effects of a peer mentor’s major on a student’s choice of major at a liberal arts women’s college. In particular, we studied whether assignment to a peer mentor from STEM v. non-STEM fields during the first year of college influences students’ choice to major in STEM v. non-STEM. The study is a natural experiment because mentors happened to be randomly assigned to students. However, the college repeatedly ran the randomization algorithm until they were satisfied with the resulting mentor assignments, and this repeated randomization implies that usual methods for analyzing data from randomized experiments are inappropriate. We will discuss a study design technique called “rerandomization” and a novel application of rerandomization methods to this natural experiment. Students’ STEM v. non-STEM choices did not appear to be affected by the STEM status of first year peer mentors at this women’s college. We will end by discussing a simulation study that illustrates the power of correctly analyzing data resulting from experiments where treatment groups were repeatedly randomized until pre-determined criteria were met.
Thursday, February 20
Glen van Brummelen
Quest University/Institute for Advanced Study
The Forgotten Man: Astronomy in the Transformative 15th Century
We know a lot less than we think. The history of mathematics is partly a record of what happened, but uncomfortably more than we might expect, over the decades it has also been a record of what we care about. We will explore one episode that illustrates the “forgotten” history of mathematics, in early 15th-century mathematical astronomy. The forgotten man is Giovanni Bianchini, the CFO from Ferrara who turned his eye away from bookkeeping and toward the heavens. His unusual path to academia provoked a number of revolutions, including among others the birth of the European tangent function. Overlooked in the shadow cast by his now more illustrious successor Regiomontanus, Bianchini’s role in the history of mathematics and science fully deserves a resurrection.
How to Make your Photos POP with Calculus
Just five or ten years ago, phone manufacturers were touting the number of megapixels in their smartphones to attract buyers. Today’s cell phones are taking better and better photos, but progress is no longer due to more megapixels but rather to algorithms, AI, and sensors that are working together to create professional-level photos. Some of these algorithms are in fact based on calculus concepts. In this talk, we’ll attempt to emulate the popular “Portrait Mode” found on current iPhones using discrete derivatives and discrete integrals of functions of two variables. The talk will be accessible to students in MA122 and beyond.
Women in Data Science conference livestream (noon to 8pm, in Olin 019B)
Women in Data Science (WiDS) aims to inspire and educate data scientists worldwide, regardless of gender, and to support women in the field. This one-day technical conference features amazing thought leaders in data science from academia, industry, non-profits, and government. Topics presented will cover a wide range of domains from data ethics and privacy, healthcare, data visualization, and more. WiDS Waterville @ Colby College is an independent event organized by Colby’s Department of Mathematics and Statistics to coincide with the annual Global WiDS Conference held at Stanford University and an estimated 150+ locations worldwide. All genders are invited to attend WiDS regional events, which feature outstanding women doing outstanding work. For WiDS Waterville @ Colby College, we will provide snacks and coffee in Olin 019B while we livestream the speakers and panels from the Global WiDS conference, starting with the Welcome at noon local time through Closing Remarks at 8pm local time. Link: Conference Program
(times listed are in the Pacific time zone).
Alexander Rasmussen ’13
Comparing and Classifying Hyperbolic Actions
In this talk we will discuss symmetries of geometric spaces, with a focus on “negatively-curved” spaces. These (so-called) hyperbolic spaces have weird geometries quite unlike that of the Euclidean space in which we live. However, they are ubiquitous in geometry and their groups of symmetries frequently have very strong algebraic and algorithmic properties. We will discuss our recent work on classifying the actions of some groups on hyperbolic spaces. Time permitting, we will discuss the connections of the corresponding proofs with number theory.
POSTPONED – March 16
University of Massachusetts Amherst
An Introduction to Model-Based Penalized Regression
Regression is an essential part of statistics. However, the kinds of scientific questions modern researchers are asking require novel regression methods. This talk will introduce some of the most popular new methods, with a special focus on model-based methods, and motivate the need for further method development research.
Colby is going to move to distance teaching after an extended Spring Break, so there will be no further colloquium talks this semester. We hope to get back to regular talks in the Fall.