statistics
posted by Bill on .
Five independent samples, each of size n, are to be drawn from a normal distribution where sigma is known. For each sample, the interval (ybar  0.96 * sigma/sqrt(n), ybar + 1.06 *sigma/sqrt(n)) will be constructed. What is the probability that at least four of the intervals will contain the unknown mu?

You take a trip by air that involves three independent flights. If there is an 68 percent chance each specific leg of the trip is on time, what is the probability all three flights arrive on time?