Probability is killing me!!!

I have having trouble understanding reading #8 (One of the last ones I need to do), has anyone else had the same problem? How did you overcome?

pls be specific.

Joint Probability is giving me alot of trouble along with when to use the mulitiplication rule and total probability rule

if you asked specific questions where you were having trouble, and people solved it for you… that will give you a better understanding and help you learn by asking more follow on questions or you could email me at and I can try and help. CP

What specifically are you having trouble with? Probability has been one of my weak areas, but that should not hinder one in understanding the concepts. If I recall correctly, joint probability was referenced in calculating expected returns and covariance. Are you having trouble with the calculations? Multiplication rule ties in with joint probability. Provide some examples and you’ll get some help. If you want a true primer on probability, try brushing up on set mathematics–unions, intersections, venn diagrams. That will at least get the ball rolling.

There’s some expertise on AF about probability. Just post your questions.

Man, always use the following reasoning and you’ll be fine. Total Probability rule refers to either of two or more events happening. Either even 1 or even 2. Use Venn Diagrams to grasp it. The probability of E1 and E2 happening together should be subtracted because you want either 1 or 2, not both. The multiplication rule is used when you want to know the probability of even 1 and 2 happening together. You simply look at event 1+2 as a whole. Tail + head is one event. Head + head is another. Got that ? It’s so easy. Probability should be the easiest part. Dont waste time here, especially when you consider the probability of getting two max three Qs on this topic.

I am also kinda struggling in this section. The probability concepts are a bit new. Joint prob and P(A/B) thing etc… I was actually excited to get to this section b/c I was excpecting combinatorics and permutations, etc… boy was I in for a rude awakening.

its actually a breeze compared to perms and comb on the GMAT