Here are remarks on preparing for the first midterm exam. I can only sample the things you should know. If you understood your homework and the lectures you should be in good shape. Know the axioms for a probability space. In particular, know that the all-important third axiom applies to a countable list of mutually exclusive events. Be able to solve for probabilities of unions or intersections of events, given other probabilities. Be able to count subsets ("n choose k") and compute likelihood of subsets with some probabilities as in the homework. Be able to use a tree diagram and compute with conditional probability. There will be a problem involving reversed conditional probabilities. Be able to compute probabilities involving independent events. Be able to make a histogram. Know the difference between continuous and discrete random variables. (An rv is continuous if every output value has probability zero, and an rv is discrete if the set of possible output values is countable.) For a discrete random variable, be able to compute the expected value, standard deviation and variance. Know the intuition: --probability of an event is its likely long term relative frequency in a series of many independent experiments --expected value of an rv X is the likely long term average of measurements using X, in a series of many independent experiments Be able to compute the cdf and pmf for an rv. Understand how to compute probabilities involving sampling with and without replacement (as in the homework problems A,B). The online testbank has samples of my midterm 1 exams from Fall 2003, Fall 2000, Spring 99 and a summer session. Good luck.