Courses & Units

Big Decisions! Rational belief and action in an uncertain world XBR111



In the modern world we must often make decisions under uncertainty, weighing up our options in the face of incomplete (and often conflicting) information. In this unit we examine the problems of evaluating evidence, forming beliefs, and making decisions based on those beliefs. We do this through the lens of Bayesianism, an intuitive view of the world that considers all beliefs and evidence to have some level of uncertainty and subjectivity.

As both a philosophical approach and an explicit mathematical system, Bayesianism is increasingly being used in real world problems across many fields. Using Bayesian approaches to deal with uncertainty is becoming essential to not only the physical and social sciences, but also to applied disciplines such as economics, marketing, law, engineering, IT, medicine and nursing. For example, what should we believe about our health based on the result of a medical test, and what treatment option, if any, should we choose? How should we evaluate evidence for climate change and what policies should we support to deal with its potential consequences? Through a Bayesian approach we can use simple arithmetic to quantify our uncertainty about the evidence, update our beliefs from that evidence, and decide on a course of action - even when there may be no single or "right" course of action.

By understanding the components of Bayesian inference, along with applications of Bayes rule to real world problems, we help students to think more deeply about how they make decisions, why they make the decisions they do, and ultimately how to make better decisions.


Unit name Big Decisions! Rational belief and action in an uncertain world
Unit code XBR111
Credit points 12.5
Faculty/School College of Health and Medicine
School of Medicine
Discipline Psychology|Mathematics|Philosophy and Gender Studies

Andrew Heathcote

Teaching staff

Andrew Heathcote, JC Beall, James Chase, Richard Corry, Barbara Holland, Melissa Humphries

Level Introductory
Available as student elective? Yes
Breadth Unit? Yes


Location Study period Attendance options Available to
Hobart Semester 2 Off-Campus International Domestic


International students
Domestic students

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Key Dates

Study Period Start date Census date WW date End date
Semester 2 15/7/2019 9/8/2019 2/9/2019 20/10/2019

* The Final WW Date is the final date from which you can withdraw from the unit without academic penalty, however you will still incur a financial liability (see withdrawal dates explained for more information).

Unit census dates currently displaying for 2019 are indicative and subject to change. Finalised census dates for 2019 will be available from the 1st October 2018.

About Census Dates



Band CSP Student Contribution Full Fee Paying (domestic) Field of Education
2 2019: $1,169.00 2019: $2,321.00 010103

Fees for next year will be published in October. The fees above only apply for the year shown.

Please note: international students should refer to this page to get an indicative course cost.



Two online assessment quizzes (2 x 30%) and a final portfolio submission (40%).

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