For many people, statistics is about simplifying systems so that some standard test (e.g., the t-test) can be applied. Over the last decade, new approaches to doing statistics have emerged that can respect the intrinsic complexity of systems. I'll introduce a couple of these approaches that focus on networks of influences: multiple regression with large numbers of explanatory variables and the topological analysis of causal networks. You don't need to know much about conventional statistics to be able to follow the talk.
This talk presents data from several experiments in neurobiology. In one type of experiment, neurobiologists insert small electrodes into the brains of living animals. The electrodes are fine enough to record electrical signals from individual neurons, so we can record when each neuron fires. Such data are called spike trains. I will show what spike trains look like, how they can be used to learn how neurons work together and how they can be used to learn how the brain encodes various sensations like taste. In another type of experiment, neurosurgeons working on human epileptic patients take a series of digital photographs of the brain. I will show how these photographs can be used to follow the path of an electrical signal across the surface of the brain and determine which regions of the brain do and don't respond to the signal.
Atul Gawande (surgeon at Brigham and Women's Hospital and faculty member at Harvard School of Public Health) asserts that research on our health care system can save more lives in the next decade than bench science, research on the genome, stem-cell research, cancer vaccine research, and everything else we hear about on the news." Janet Rosenbaum will discuss how public health addresses virtually every medical and social issue, and it does so at the population level where it can have the greatest impact. The speaker will outline problems in public health, and give examples from her work on adolescents' lying about sex and virginity pledges, and using tobacco taxes to reduce smoking in the developing world and New York City.
The US spends $200 million annually on abstinence programs, including virginity pledges. Using data from Add Health waves 1-3, adolescents reporting a wave 2 virginity pledge (n=289) were matched with non- pledgers (n=645) using exact and nearest-neighbor matching on wave 1 factors including pre-pledge religiosity, attitudes towards sex and birth control, and family context. Wave 3 outcomes were compared. Five years post-pledge, 84% of pledgers reported having never taken a pledge; pledgers and matched non-pledgers did not differ in premarital sex, sexually transmitted diseases, and oral and anal sex. Pledgers had 0.1 fewer past year partners, but the same number of lifetime sexual partners and same age of sexual initiation. The sexual behavior of virginity pledgers do not differ from that of comparable non- pledgers, but pledgers were less likely to use birth control and condoms in the past year and birth control at last sex. Virginity pledges may not affect sexual behavior, but may decrease the likelihood of taking precautions during sex.
Thanks to the Smith College Lecture committee, Department of Mathematics and Statistics, and Office of the Dean of the Faculty for support of the series.
Applied Statistics Lecture series (2006-2007)
Other 5 college seminars of interest:
University of Massachusetts Statistics and
Probability Seminar Series
Organized by Nicholas Horton.
Last updated November 20, 2008