Searching within an ordered hierarchical setting can improve the search. But, it is not immediately obvious how to setup the data structure to support this type of search. In this part of the course we explore how to define a biased walk, based on information, to quickly find an 'odd one out'. From this concept of walking along a tree structure, we then move into thinking about how to best setup that tree structure.

Many real-world applications have extremely large action and/or hypothesis spaces. For the application of Chernoff's ideas there has to be a way to apply the algorithms quickly at scale. In this set of material we examine how approximations may work and how Chernoff's ideas have been extended to different types of problems.

The ideas that we have been exploring can also be applied to data slices collected at disparate windows in time, can be applied to improving MRI scans and can be applied to molecular protein design. These applications all share the concept of using sequential hypothesis testing to improve understanding. In addition, all three of these ideas are under active code development.

In our fifth week we explore how to move beyond the 'odd one out' and into multiple hypothesis testing for streams of data. This could be for setting a dosage level on a medication or on how to identify objects in a set of images.