expectation

Posted by hs on Jun 13, 2014; 10:57pm
URL: http://discussion-forum.276.s1.nabble.com/expectation-tp7592678.html

Suppose that a person repeatedly tries to perform a certain
task until he is successful. Suppose also that the probability of success on each given
trial is p (0 <p <1) and that all trials are independent. If X denotes the number
of the trial on which the first success is obtained, then E(X) is ??