Hey, guys, I was wondering if you could help me with some statistics and physics. http://www.trin.cam.ac.uk/show.php?dowid=475 Questions 2, 4, 5, 6, 9 and 10. Thank you :)

Question

youngster · Answer

for number two, make a "tree" i guess, it might help.
sorry, im still learning statistics
there is a formula for how to find the probablity of B given A, but I can't seem to get it on here. :(

anonymous · Answer

Thanks nonetheless... :)

anonymous · Answer

@mandja for #2 what is the probability for a false positive?  Are we to assume it is zero?

anonymous · Answer

Assuming that the test is 95% accurate for the positive and for 100% accurate for the negative, this is solvable: Let $C$ denote having the condition and positive/negative signs denote the results.  Given is this:
$$P(C)=0.001$$$$P(+|C) = 0.95$$$$P(\lnot C)=1-P(C) = 0.999$$$$P(+|\lnot C)=P(\lnot C\land+)/P(\lnot C)=0.05$$Then,$$P(C|+)=\frac{P(+\land C)}{P(+)}$$Since $P(+) = P(+|\lnot C)P(\lnot C) + P(+|C)P(C)$, we can just plug in the values to get: 1.8%

anonymous · Answer

Thanks. For the 4-th question I'm thinking of binomial distribution?