Multiple perspectives on the concept of conditional probability

Conditional probability is a key to the subjectivist theory of probability; however, it plays a subsidiary role in the usual conception of probability where its counterpart, namely independence is of basic importance. The paper investigates these concepts from various perspectives in order to shed light on their multi-faceted character. We will include the mathematical, philosophical, and educational perspectives. Furthermore, we will inspect conditional probability from the corners of competing ideas and solving strategies. For the comprehension of conditional probability, a wider approach is urgently needed to overcome the well-known problems in learning the concepts, which seem nearly unaffected by teaching

B Physics at the Tevatron

After a five year upgrade period, the Fermilab experiments CDF and DO are taking high quality data in Run II of the Tevatron Collider. We report on the start-up of both detectors and present a selection of first B physics results from the Tevatron. We also compare different B hadron producers such as the Y(4S) with the hadron collider environment and discuss general features of B physics at a hadron collider.Comment: Posting for the archives: Invited review talk to appear in proceedings of "Physics at LHC" Conference held in Prague 200