I have an interview with Susquehanna on friday and the lady on the phone told me to expect so "basic" probability problems. What types of questions should I expect? Also, how should I go about practicing for such questions? I would REALLY appreciate any information you guys can provide. Thanks a lot.

book, a summary of basic concepts with examples. Something like 'Probability and Statistics'. Anyway, I don't know what they can expect you to know, but I would think that at least what is in this book, if not more.

Here is a guess. What is the probability of a data point lying outside of a three sigma band or circle. Answer: I can't remember.

The most difficult question they will ask you will probably be something like: If coin blanks are manufactured in such a way that they contain 1.001 oz of gold on average, and 65% of all blanks contain between 1.0008 and 1.0012 oz, what percentage will contain less than 1 oz. Assume a normal distribution.

As electron says, get a good introductory book. Apart from remembering a few basic formulae and doing some exercises, there's not really much you can do to prepare for something like this. Most of the time you'll have to compute the fraction whose numerator and denominator is (number of favorable outcomes) and (total number of possible outcomes), respectively. Therefore, make sure your book also covers simple combinatorics (permutations and combinations).

In the featured horse race at Belmont, I am trying to pick the "trifecta", that is, the top three finishers in the race. I like 4 horses, but none in any particular order. I want to buy a "trifecta box" ticket which encompasses every combination of the 4 horses to finish in the top 3 spots. If each combination/ticket costs $1, how much will it cost me to purchase a trifecta box ticket using all 4 horses in a 6 horse field? How about in a 9 horse field?

4_P_3 or $24. And why would the number of horses in the race matter? Careful, knowledgebone, this is not a probability question. And don't confuse James' lack of preference with the definition of "trifecta".